What does a stool occult blood test tell? How to properly submit stool for occult blood testing

In order for a stool occult blood test to show reliable results, appropriate preparation is necessary. The diagnosis and prescribed treatment depend on laboratory test results. Be sure to follow all your doctor’s recommendations regarding diet before collecting material.

Why do you need to get tested?

Already from the name of the laboratory test it is clear what a fecal occult blood test shows. Then the question arises: to whom and for what purposes is it prescribed? This analysis allows us to detect the presence of bleeding in the gastrointestinal tract, which, in turn, can occur for a variety of reasons. For example, according to these:

When there is heavy bleeding in the small intestine, the stool may turn black

intestinal inflammation;
ulcerative colitis;
stomach and/or duodenal ulcer;
diffuse familial polyposis;
polyps in the large intestine;
cirrhosis of the liver;
hemorrhoids and anal fissure;
helminth damage.

If you have a history of one of these pathologies or its symptoms, stool tests for occult blood are indicated.

Preparation and delivery of analysis for adults

This analysis may be relevant for diagnosing various gastrointestinal diseases in both adults and children. For a transcript, see the article at the link.

When prescribing a stool test for occult blood, the doctor must tell you that special preparation is required before this laboratory test.

6 mandatory stages of preparation

A week before donating stool, stop taking medications, especially those that can affect gastrointestinal motility and the color of the material. This rule applies to all forms of medications, including oral (tablets, capsules, mixtures, infusions) and rectal (oils and suppositories).
Before taking the test, strict adherence to the diet will be required. Excluding certain foods from your diet (read which ones exactly) no less than 72 hours before the day of collection.
Defecation to collect material should only be spontaneous. No enemas or laxatives.
If any diagnostic examinations in the intestinal or stomach area have been prescribed, for example, sigmoidoscopy or endoscopy, it is necessary to reschedule them for another time (after collecting stool for analysis).
Although this rule contradicts hygienic standards, it is recommended that the night before donating feces not brush your teeth, but simply rinse your mouth. The fact is that even the most microscopic trauma to the gums can affect the results of the study.
During menstruation, women cannot have their stool tested for occult blood testing. We will have to reschedule the study for another day.

Kirimov P.A., proctologist, Health Plus Clinic, Moscow

After 40 years, the risk of cancer is known to increase.

Therefore, even if there are no health complaints, you should definitely come to your local physician for a referral for testing, or get examined in a private clinic.

Diet before tests

What should be the diet of the examined patient should be indicated separately. A special diet must be followed for at least 3 days before a stool test for occult blood.

Preparation and diet are key when taking the test

The Gregersen method used in this analysis is sensitive to iron., so it is strongly recommended to exclude all products containing this element.

You should also remove from the menu foods that can change the color of stool (blueberries, beets), contribute to constipation (rice, baked goods made from premium flour) or have a laxative effect (prunes, strawberries), causing flatulence (legumes, carbonated water).

So, you will need to exclude from your diet everything that can make the results of a stool occult blood test false:

fish and some seafood;
meat and offal;
most vegetables (especially those that contain a lot of iron or have a laxative effect);
fresh apples;
berries, especially blueberries, strawberries and black currants.

What can you eat in this case? Include grain bread, butter, various cereals, chicken or quail eggs, and dairy products in your diet. Baked or boiled potatoes and some fruits are allowed in small quantities.

The container for the test material must be sterile

The container for transporting stool must be sterile. As a rule, this is a plastic or glass container with a tight-fitting lid. When using non-standard containers, you must boil them. described in detail in our article at the link.
After defecation, the material must be collected from 3-4 places in a single portion. A volume equal to half a teaspoon will be sufficient. Contact with feces of discharge from the genitourinary tract is unacceptable.
The sooner the material is delivered to the laboratory for research, the better. You can store it in a special container for a maximum of 12 hours, and the temperature should be from +4 to +8. If these conditions are not met, the result will be false.

How to properly prepare and take the test for your child

Parents are responsible not only for their own health, but also for the health of their children. You need to be attentive to the child’s well-being and mood, and do not ignore complaints of pain. Babies who cannot speak express their anxiety by crying loudly and incessantly. and if stool retention or diarrhea is observed, it is necessary to urgently take a stool test, including for occult blood.

Preparation

All recommendations for preparing for the analysis, including a special diet and drug withdrawal, are followed in children in the same way as in adults. Soda and various sweets with dyes are harmful to the gastrointestinal tract, and if you have not yet limited your child from consuming them, you definitely need to do this when preparing to donate stool.

Children in the first months of life usually feed only on mother's milk. Therefore, in order for a fecal occult blood test in a baby to be reliable, a nursing mother must follow an appropriate diet and temporarily exclude medications. and read the articles at the link.

Polyakova V.I., pediatrician, children's clinic No. 1, Voronezh

Pathologies of the gastrointestinal tract are not always manifested by painful sensations, frequent bowel movements or delayed bowel movements.

After each baby's bowel movement, carefully examine the contents of the potty or diaper.

Collection, storage and transportation of material

General recommendations on how to collect a stool test for occult blood have already been described above. Urine should not enter the container. To collect and deliver the material, it is not advisable to wear a diaper on the baby, as this may spoil the picture of the results. It is best to use a clean cloth oilcloth.

As for older children, take feces after defecation from the toilet are unacceptable. Ask the child to sit in the pot, which should first be doused with boiling water.

Children's feces should also be stored at a temperature of +4 to +8 and transported to the laboratory no later than 12 hours.

We decipher the results: norm and deviation, false positive and false negative

A stool occult blood test, like any other laboratory test, is always interpreted by the attending physician. You shouldn’t draw any conclusions on your own, much less self-medicate..

Norms and deviations in adults

The norm for a stool occult blood test is a negative result.. But it is worth understanding that 1-2 ml of blood still ends up in the intestines. This will also be considered a variant of the norm, but only in the case when stool is no more than once a day.

If a stool test for occult blood is negative, but other studies indicate the presence of gastrointestinal pathologies (for example, endoscopy clearly reveals polyps in the rectum), the result is considered false negative.

A positive result in most cases indicates the presence of pathologies of the gastrointestinal tract and liver. These can be polyps, ulcers, fissures, hemorrhoids and even a malignant tumor. To clarify the diagnosis, other research methods will be required.

If the stool occult blood test is positive, you should not immediately panic. Before making a diagnosis, the doctor will prescribe a repeat examination. It is quite possible that the results are false. Distortions may arise for the following reasons:

failure to follow a special diet and other recommendations before the study;
bleeding in any part of the gastrointestinal tract is still present, but is temporary;
bleeding of the gums and nasal mucosa (you should definitely inform your doctor about this).

In addition, errors on the part of the laboratory cannot be ruled out. Such cases are rare, but they do happen.

Norms and deviations in children

There should be no blood in children's stool, as in adults.(more about). But it should be understood that during the first 3 months of life, the baby’s body adapts to extrauterine life, and the gastrointestinal tract still continues to form. Therefore, if a test showed hidden blood in the stool of a small child, minor deviations from the norm are allowed.

If hidden blood was detected in the stool, the doctor will give a referral for additional examination

The fact is that in an unformed intestine, the vessels are located very close to the surface and are easily deformed during defecation, and even with severe gas formation.

In this case, as well as with bleeding gums during teething, and with improper preparation for the analysis, a false positive result is possible.

But we also cannot let the situation take its course. First of all, you need to try to bring the baby’s stool back to normal by reviewing it. In case of gas formation, place the child on his tummy more often and give dill water. After these steps, be sure to retake the stool test, and if necessary, the pediatrician will prescribe a hardware examination.

Even in the absence of complaints, it is necessary to examine stool in older children at least once every six months for preventive purposes.

The presence of hidden blood in a child’s stool can often indicate damage to the liver and gastrointestinal tract by helminths. This disease occurs quite often in childhood, however, there are no obvious symptoms. Therefore it is important to know.

In pediatrics, medical prescriptions should be treated with particular caution. Unpromising and aggressive treatment can harm the child’s health. It is necessary to strictly monitor all indicators, for example, to know what the blood sugar level is in children.

Conclusion

Unfortunately, in the modern world there are very few completely healthy people. This situation is further aggravated by the fact that many pathologies are hidden and are detected already in an advanced stage.

In order to detect the disease on time, regular diagnosis is necessary.: hardware and laboratory research. If the analysis is normal, but complaints persist, the studies should be repeated, as well as additional diagnostics, for example, ultrasound, endoscopy, sigmoidoscopy, FGDS. Remember, our health is in our hands.

Particular attention is required when preparing for a stool occult blood test, since if it is absent or performed incorrectly, false positive results may be obtained.

Indications for the purpose of analysis

Examination of stool for blood hidden in it is prescribed for the following patient complaints:

Constant/recurrent abdominal pain;
frequent symptoms of dyspeptic disorder - nausea, vomiting, heartburn;
regular diarrhea;
unexplained weight loss.

Testing stool for blood present in its composition is prescribed to confirm the diagnosis, for example, peptic ulcer or erosive gastritis. The overall goal of the analysis is to identify hidden damage to the mucous membranes of the stomach or intestinal tract.

Types of tests

If there are bleeding areas of the mucosa, blood may be present in a person's excrement. If the site of bleeding is the stomach or duodenum, then the stool becomes dark red in color. When the surface of the large intestine is damaged, they become scarlet. But it is not always possible to see blood impurities in a person’s stool. Very often, small ulcers bleed only periodically.

The study is performed in two ways:

Gregersen method (benzidine test);
immunochemical test.

The Gregersen test is quite informative, but only if the patient has thoroughly prepared

Gregersen's technique allows you to detect even the minimum concentration of hemoglobin. This is both an advantage and a disadvantage of the method. Benzodine colors iron molecules blue, but it reacts with both human and foreign hemoglobin (present in meat).

The immunochemical method is more accurate. Its significant drawback is that it takes quite a long time. Test results will be received only two weeks after submitting the material for research. Therefore, in most cases, stool testing is prescribed using the Gregersen method.

Preparing for the Gregersen test

To get the most reliable results, you need to properly prepare for stool donation. The recommendations will be as follows:

A week before the planned delivery, it is necessary to stop taking medications such as laxatives, bismuth- and iron-containing drugs, and non-steroidal anti-inflammatory drugs. It is prohibited to use acetylsalicylic acid and medications containing it.
It is necessary to avoid administering rectal suppositories.
Enema is prohibited.
Before testing stool for occult blood - two days before the test - you need to exclude any instrumental tests of the gastrointestinal tract. During the study, the mucous membrane may be accidentally damaged. Released blood may cause false positive results.
A few days before collecting excrement, you should stop brushing your teeth. Even a small amount of blood released when the gums are damaged can enter the stomach. And this hemoglobin can also negatively affect the final result.

The main point of preparing for the test is strict adherence to the diet.

The patient's diet should completely exclude foods high in iron. The collection of stool must be preceded by refusal:

Ideally, in order not to make a mistake with the menu, doctors recommend adhering to a dairy diet during the days of preparation for donating stool. The diet may also include:

potato;
bread;
porridge (with the exception of buckwheat, oatmeal, egg, lentils, peas).

Collection of stool for research

Even careful preparation will be completely useless if the biological material is collected incorrectly.

There are special containers for transporting feces to the laboratory - they are sterile and guarantee the biological purity of the collected excrement

How to pass feces correctly? To obtain material suitable for research, you must follow the following recommendations:

A sterile container must be used to collect excrement. It can be purchased at any pharmacy. The set includes a jar with a lid and a special spoon.
First you need to empty your bladder. Then place an oilcloth in the toilet.
After bowel movements, it is necessary to take three portions of feces from different places.

The material must be delivered to the laboratory within the next three hours. It cannot be stored.

False results

Failure to follow the preparation rules before donating stool may result in erroneous results. They can be either false positive or false negative.

The main reason for false-positive tests indicating the presence of internal bleeding is improper preparation.

False positive results are quite common. The reason is a person’s disdainful attitude towards the preparatory stage. In this case, the test shows a high hemoglobin content in the absence of internal bleeding. Just one apple eaten a day before the delivery of biological material can distort the final results.

Proper preparation for examining stool for occult blood in many cases allows you to avoid a very unpleasant colonoscopy procedure. The technique involves examining the intestines by inserting equipment through the anus.

Feces for occult blood: preparation, diet, interpretation of results

In order to determine the condition of the human body, you need to undergo an examination and submit some materials to a laboratory for research. There are a large number of types of tests, one of them is feces for occult blood. Preparation takes several days.

Collection of stool for occult blood: indications

The analysis is needed to determine whether there is damage to the gastrointestinal tract. If the integrity of the mucous membrane of at least one organ is compromised, this will be visible in the results.

The reason for the analysis may be:

Severe intestinal diseases;
Ulcer;
Colitis;
Polyps;
Anemia;
Poor appetite;
Abnormal stool;
A sharp change in weight downwards;
Frequent constipation;
Heartburn;
Acute pain in the abdominal area;
Constant nausea.

In addition, feces for occult blood are taken if there is a suspicion of cancer or a benign neoplasm.

You can get a referral for analysis from a surgeon, therapist, oncologist or gastroenterologist.

What do you need to know about the study?

At the present stage, everyone who undergoes an occult blood test needs to have at least general information on this matter.

The fresher the sample, the more accurate the results will be.

Before taking samples, simple preparation is required for several days.

The daily amount of dense excrement is approximately 200 grams. Significantly more comes out with pathological processes of the gastrointestinal tract, less with malnutrition, consumption of protein foods, and problems with bowel movements.

By the form you can understand whether there are deviations in the functioning of the intestines. In a healthy person, stool is sausage-shaped, medium-density, brown in color. If abnormal, excrement can be very dense or liquid, lumps or in the form of a ribbon. In severe pathologies, not only the appearance changes, but also the composition, smell, and various impurities appear.

Normal feces may contain particles of undigested food - the norm is the peel of fruits or vegetables, cartilage or tendons.

If mucus or blood is visible to the naked eye, this indicates a disease of the colon.

How to properly test stool for occult blood?

Almost all patients know how medical staff should behave. However, few people remember that there are also general recommendations for patients regarding taking any test, including stool. They are as follows.

Feces are collected after natural bowel movements. The use of enemas or laxatives is prohibited. It is not recommended to use it several hours before sample collection, and special preparations for another 3-4 days. If you break this rule, the analysis will not be accurate. However, this only applies when feces are tested for occult blood.

The accuracy of the results depends on the freshness of the material. The ideal option is if the sample reaches the laboratory within 3-6.5 hours after its collection. This rule is not always easy to follow, however, some microorganisms live outside for only a few hours. Therefore, it becomes increasingly difficult to obtain a complete picture over time. It is advisable to take the test before 10 o'clock.

3-4 days before submitting samples, special preparation is needed - following a diet. You should not eat a lot of foods that cause discomfort in the stomach and intestines. Avoid foods that stain excrement, such as beets, greens, and some fruits.

If possible, do not take pharmaceutical drugs a week before collecting samples. The exception is those taken regularly for chronic diseases. This is due to the fact that some medications color the stool a different color or change the composition of the microflora. In addition, do not conduct additional bowel examinations using special enemas, such as barium. It discolors feces and changes their structure.

Collect the sample in a special jar-container with a spoon; it must be purchased in advance. To make an accurate analysis, a few grams of material is enough.

The last rule applies to women. It is not recommended to take material during menstruation, as blood can get into the excrement and spoil the results.

Diet before stool occult blood test

A few days before the samples are taken, a special diet is prescribed, which must be followed in order for the analysis to be correct the first time.

During this period you should not eat:

Liver in any form;
Legumes;
Fish and meat dishes;
Apples and other fruits that affect the color of feces;
Greens, particularly spinach;
Some vegetables: tomatoes, sweet peppers, beets, hot horseradish.

Sample menu for one day:

Bread and butter, milk soup, some pears or peaches, canned in winter;
Mashed potatoes, 2 boiled eggs, milk jelly;
Yogurt without dye;
A glass of kefir or fruit.

The amount of food taken at one time should not exceed 1 gram. The same set of foods with some corrections and variations should be eaten for another 2 days.

Feces for occult blood: interpretation

The finished analysis, interpretation, is called a coprogram. First of all, feces are not characterized by the presence of blood, even in the form of individual cells. Therefore, microscopic examination is done to find out whether red blood cells are present in the excrement?

They can be there for several reasons: damage to the stomach and small intestine or the lower part, that is, the rectum, colon and anus. If the bleeding is severe, the discharge is already noticeable - the feces will be black; in the case of minor damage, it is difficult to determine anything without special studies.

Damage to the lower part of the digestive system is noticeable due to the presence of bright red impurities. Since some foods and medications can have a similar effect, you need to undergo diagnostics, that is, donate feces.

This analysis will indicate whether there are problems at the top of the food system if red blood cells are present in the material provided for the study. There are no special standards for this; even the smallest amount of blood particles in the feces is enough.

If the gums or nasal mucosa bleed, the test will be positive. Therefore, careful preparation for the procedure is necessary, and it is not recommended to brush your teeth the day before and try to avoid various injuries.

Fecal occult blood test

Fecal occult blood test - detects “hidden” blood that is not visible under microscopic examination.

What does a stool occult blood test show?

The presence of bleeding from any part of the digestive tract.

What are the indications for prescribing the test?

Suspicion of bleeding from any part of the gastrointestinal tract.

How to prepare for research?

7-10 days before the test, stop taking medications (all laxatives, bismuth, iron). You can't do enemas the day before. After an X-ray examination of the stomach and intestines, a stool test is scheduled no earlier than two days later.

Three days before the analysis, exclude meat, liver and all foods containing iron from the diet (apples, bell peppers, spinach, white beans, green onions).

How to properly collect stool for research?

Feces are collected after spontaneous bowel movements in a disposable plastic container with an airtight lid. Urine mixed into stool should be avoided

The container with stool must be delivered to the laboratory on the day of collection of the material, and stored in the refrigerator (4-6 C 0) until shipment.

Feces for occult blood - what is it?

Taking stool for analysis to detect the presence of occult blood is one of the modern diagnostic methods that allows for the timely detection of a number of serious gastrointestinal diseases. Probably every adult knows that blood in stool is dangerous. And when they discover bloody discharge in their own stool, many deliberately rush to go to the doctor. But the fact is that the stage when blood is clearly visible in the stool is far from the first stage of the disease. And often the success of treatment when this type of bleeding is detected is not as clear as if the blood was detected earlier.

Many diseases of the digestive organs, of the entire complex digestive system, at the initial stage may not manifest themselves with any symptoms, much less heavy internal bleeding. But microparticles of blood are already present in the body and are removed from it along with feces. Only they are so small that it is impossible to see them even if you look closely at your own excrement (which most people, for obvious reasons, usually do not do). In this case, an analysis is carried out for the presence of occult blood.

Fecal occult blood test

Today, this analysis is prescribed to all patients over fifty years of age, once, annually. Age groups under 50 take it according to indications.

Why do you need a test to detect blood in stool?

In what cases is this analysis prescribed? For what reasons do doctors suddenly start looking for hidden blood in a patient’s stool? This is done if a number of diseases are suspected.

A stool sample for occult blood testing is a common laboratory test such as a complete blood count or urinalysis. It can be used to identify subtle internal bleeding that is present:

in any part of the intestine;
in the stomach;
in all organs of the digestive system, without exception.

Most often, blood in the stool appears due to serious damage to the stomach, intestines or duodenum, which leads to anemia and other dangerous consequences

Agree, “seeing” what is happening inside the digestive system, especially in the endless intestines, the total length of which in an adult is about eight meters (five times his height), is quite difficult. Moreover, the structure of the intestines is intricate, and the location is tortuous.

By the way. At the same time, the digestive and excretory tract is the most “risky” organ, containing a record number of bacteria, through which toxic and other waste from the activity of the entire body is eliminated. It is easiest for harmful microbes, tumors, ruptures and damage to “hide” here.

Indications

Doctors prescribe stool testing for occult blood quite often. The following patient symptoms and complaints may be indications for analysis.

Abdominal pain (localized in the abdominal area) of unknown etiology.
A feeling of nausea that continues for a long time in the absence of diagnosed gastrointestinal diseases.

Constant feeling of nausea

Varicose veins in the esophagus

There are conditions under which stool examination to detect occult blood cannot be carried out until the circumstances change:

dyspepsia;
menstruation;
bleeding hemorrhoids;
hematuria (when blood is found in the urine);
periodontal disease.

In parallel with the stool examination, a leukocyte blood test, biochemistry, general urine examination, kidney tests and tumor markers are prescribed.

Blood test norms

Important! If you receive a positive test result, which was detected in the laboratory or during a test at home, a colonoscopy of the intestines is recommended. A negative result reduces the risk of most serious diseases, but does not completely exclude it. It is necessary to compare the result with other tests prescribed in parallel.

How to improve research efficiency

The effectiveness of the study depends on how thoroughly the patient prepares for the test. Scrupulous fulfillment of all requirements placed on the patient is the key to the accuracy of the result obtained.

General preparation for stool testing for occult blood is carried out as follows.

Start of preparation – 7 days before the analysis. From this time on, all medications that tend to color stool are discontinued. It is also necessary to stop taking medications that affect intestinal motility.

As prescribed by the attending physician, a week before the stool donation procedure, all medications are canceled

Foods that can stain the intestines should be excluded from the menu, which will distort the results of the study.

Vegetables, fruits, and juices that affect peristalsis are excluded from the diet

Laxatives should not be taken before the procedure.

X-rays are taken no later than three days before examining stool for occult blood.

Women should choose the right day for testing

Better to use mouthwash

Before the test procedure, it is important to avoid any traumatic penetrations

Important! Blood hidden in stool is an indicator of multiple diseases, but most importantly, it can be a signal of malignant diseases. The very first warning about the appearance of cancerous tumors in the intestines throughout its entire area, the esophagus and stomach. Of course, the earlier you start treating cancer, the more likely it is to defeat it.

Rules for sampling

When collecting stool for analysis, a number of rules must be followed.

Do not try to collect stool with an enema - bowel movements should occur naturally.
Collect feces in the morning, after waking up, preferably before breakfast.
Before collecting, urinate and thoroughly wash the genitals and sphincter.
Use a special wooden spatula and a test container with a tight lid for collection; it can be made of plastic or glass.

Container for analysis

How to test feces for occult blood

Important! The study is carried out over six days. The result of the norm is negative. This does not mean that there is absolutely no blood in the stool. But this means that its presence does not exceed acceptable limits. If the norm is exceeded, the result is declared positive.

Types of tests for occult blood in stool

This test can be done in three different ways. The material under study is analyzed using:

guaiac test;
immunological test;
Gregersen reactions.

Benzidine stool occult blood test (Gregersen test)

Table. Type of analysis and description.

No preparation may be required because the latest generation of immune tests do not react with iron, blood or other reactive substances. But before taking this test, you need to ask the pharmacy or laboratory what tests are used. When using a sample that reacts with other substances, general preparation is required.

Specifics of preparation for the guaiac test

Before passing the guaiac test, you must remove from use three days before:

pork and beef meat and offal;

Meat and offal

Where is vitamin C found?

Specifics of preparation for the benzidine test

Here, too, it is important not to violate the rules of preparation and carefully follow them.

The following are excluded from the menu three days before delivery:

Liver and offal

Decoding the results

The test can be positive or negative. In the second case, this means that the blood is flowing normally. In any case, blood is secreted in the body of every person. It moves through the intestines, breaking down under the action of enzymes, but if its amount does not exceed 0.2 mg of hemoglobin per 1 g of feces, the result is considered negative, and blood in the feces is considered absent.

If the result is positive, the values exceed the declared value, sometimes several tens of times.

It is worth considering when deciphering that a sample can be either false negative or false positive. If there is bleeding of an intermittent nature, for example, with polyps, this analysis may have a negative result. For an accurate diagnosis, it is necessary to repeat the test.

Conversely, if the mucous membrane is accidentally injured, even if this happened during the morning brushing of teeth or a nosebleed that occurred the day before, as well as when consuming foods and preparations containing iron, the result can be positive in the absence of any disease.

Important! If the test is negative, it is therefore necessary to repeat it and confirm it. If the test is positive, it is also recommended to conduct a confirmatory test and prescribe further examinations to the patient.

The importance of this analysis in the diagnosis of most gastrointestinal diseases is very great.

There are open and obvious bleedings that change the stool to such an extent that their presence can be visually determined. For example, when blood leaves the lower segments of the colon, it turns the stool scarlet and can collect in large clots or wide veins. If the source of bleeding is located in the upper part of the gastrointestinal tract, the stool darkens, acquires the color and consistency of tar, since the blood, reacting with gastric enzymes, modifies it.

The color of stool can determine the location of bleeding

Important! If bleeding is visually detected, the situation is certainly an emergency, requiring immediate medical attention, including surgical intervention. But this does not mean that hidden bleeding is less dangerous.

Traditional tests have many shortcomings and errors, however, examining stool for the presence of occult blood helps to diagnose many diseases so effectively that there is no such safe and painless, non-traumatic and quick alternative.

Tests for the presence of blood are positive in 97% of cases of colon cancer, in 60% of cases of adenomatous polyposis (with a diameter of 1 cm) and other dangerous diseases. It has been statistically proven that detecting cancer in its early stages reduces the mortality rate from this disease by an average of 30%.

How to donate and what does a stool occult blood test show?

Blood during bowel movements may indicate a serious illness, ranging from an anal fissure to a malignant neoplasm in the digestive organs.

However, in the early stages, the pathology often develops without obvious symptoms, and hidden bleeding can be difficult to notice.

A stool occult blood test detects the smallest impurities of blood and allows you to diagnose diseases in the initial phases, which is extremely important if cancer is suspected.

In what cases is it prescribed?

A stool occult blood test is prescribed for the following symptoms:

Stomach ache;
Dyspeptic symptoms (heartburn, bloating, nausea) for a long time;
Frequent diarrhea, constantly thin stool;
Other digestive disorders;
Sudden weight loss for no apparent reason;
Clinical stool analysis does not show the presence of bleeding.

The presence of occult blood must be checked if inflammation of the gastrointestinal tract, peptic ulcer, or neoplasm is suspected.

The indications for this test are quite serious, and if the doctor suggests doing a stool test, you should not ignore his recommendations. Unlike many other methods of examining the gastrointestinal tract, the test is completely safe and painless.

Research methods

Modern laboratories use 2 main analysis methods:

The Gregersen test, as a chemical test for occult blood is called, is used to detect bleeding in all parts of the gastrointestinal tract. The test is sensitive to hemoglobin of both humans and animals, so special preparation and a meat-free diet are required before taking it.
A stool occult blood test using an immunochemical method is prescribed to diagnose pathologies of the lower part of the digestive tract. The test only tests human hemoglobin, so patients do not need to limit their diets to meat and iron-rich foods. A stool occult blood test without diet is more convenient and is widely used as a screening test for colorectal cancer.

Immunochemical analysis is considered more modern and sensitive, but it is not informative regarding bleeding in the esophagus and stomach.

The choice of method is made by the doctor, depending on the patient’s complaints. Before going to the laboratory, consult a specialist!

How to prepare?

Patient preparation depends on the chosen research technique.

Taking a stool occult blood test using the immunochemical method does not require changes in diet.

2 weeks before it you should refuse:

From drugs that increase the risk of bleeding (aspirin, ibuprofen).
From laxatives.
From procedures that can damage the mucous membranes of the gastrointestinal tract (enemas, colonoscopy, etc.).

Preparation for analysis using chemical samples includes a special diet. The Gregersen reaction can give a false result for digested hemoglobin and myoglobin in meat products, and for some vitamins and nutrients.

When testing for fecal blood, the diet excludes:

The diet should begin 3 to 4 days before the study, in addition, during this period you should:

Avoid taking medications, foods, and drinks that can stain stool and affect intestinal motility;
Avoid enzymes;
Do not use rectal suppositories;
Postpone x-ray examination of the gastrointestinal tract;
Replace brushing with hygienic rinsing to prevent damage to the gums and blood from entering the esophagus from the oral cavity;
Women do not test fecal occult blood during menstruation and 3 days before and after it.

How to assemble?

Proper preparation and delivery of the analysis affect the reliability of its results.

In no case should foreign impurities enter the test material: water, urine, genital secretions, X-ray contrast compounds, suppository components, etc.

How to prepare for stool collection:

Purchase a sterile container. It is a container with a screw cap and a spoon. Containers are sold in pharmacies and laboratories.
Disinfect the vessel, pot, or other container suitable for defecation. Wash with soap, rinse several times with clean water, and pour over boiling water. You cannot collect feces from the toilet.

Only natural feces are suitable for research, without laxatives or enemas.
You should defecate in a prepared container, avoiding urine.
Use a special spoon to take the feces and transfer the material into a container.
Close the lid.
Attach a stool occult blood test form issued by the laboratory or prescribed by a doctor to the container.

The amount of feces for analysis is no less than a teaspoon and no more than 1/3 of the volume of the container. It is advisable to take not one, but several fragments of stool, so that the detection of hidden blood is as effective as possible.

How to submit?

Prepared feces cannot be stored; only fresh material that has not been frozen or preserved is suitable for analysis.

The best option for handing over a container, if it is not possible to deliver it to the laboratory immediately, is to put it in the refrigerator at a temperature of + 2 - 8°C, and transport it in a thermos with an ice cube. Maximum storage time is no more than 3 hours.

The result of a stool occult blood test is prepared within a few days. Typically, the study period is 3–6 days, depending on how long the analysis is done in a particular laboratory.

Analysis results

The norm for excretion of blood in the feces of a healthy person is up to 2 mg of hemoglobin per 1 g of material. A positive result means that occult blood has been detected in the feces, but its source must be further identified.

The intensity of the reaction is expressed by the number of “pluses”: from one – weakly positive, to four.

The Gregersen occult blood test may show:

Erosive gastroduodenitis;
Exacerbation of ulcers;
Tumor in the stomach, intestines;
Diverticulum;
Varicose veins of the esophagus;
Haemorrhoids;
Intestinal tuberculosis;
Crohn's disease;
Polyps;
Nonspecific ulcerative colitis.

With the chemical research method, there may be other reasons for hidden blood in stool analysis that are not related to gastrointestinal diseases.

A false positive result is likely if the diet is not followed before donating stool, if there is bleeding in the nasopharynx, helminthic infestation, blood diseases, or menstruation. A fecal occult blood test in infants can be positive in cases of allergies, lactase deficiency, and constipation.

What the immunochemical method shows: a result >50 ng/ml indicates hemorrhoids, polyps, colorectal carcinoma, ulcerative colitis or Crohn's disease.

A physician should interpret laboratory results. If the test for occult blood in the stool is positive, additional diagnostic measures need to be carried out to clarify the pathology.

Where to do it?

Having received a referral for testing, the patient himself has the right to choose where to donate stool for hidden blood: in a public clinic or a private laboratory (Invitro, Helix and others).

The price of the service is in the range of 350 – 700 rubles, depending on the technique used.

An immunochromatographic stool occult blood test has been developed for use at home. This is a quick and simple tablet test that detects human hemoglobin cells in feces.

How to do the analysis yourself:

Purchase a test at the pharmacy to diagnose hemoglobin in human stool;
Open the package;
Collect feces with a special applicator into a container with a reagent;
Place 2 drops of liquid onto the indicator tablet;
Wait for the result.

By following the algorithm, you can quickly and with a high degree of confidence (up to 99.9%) detect the presence of bleeding in the gastrointestinal tract: two strips - test and control, which means the stool test for occult blood is positive and it is necessary to urgently contact a specialist.

Normally, blood should not be found in the stool, but there are pathological conditions in which such a phenomenon is considered one of the characteristic signs.

Hidden blood is a specific condition in which bloody masses in the stool are not visible to the naked eye, even under a microscope, however, with a deeper study of the biomaterial, the presence of blood is revealed.

Types of stool tests for occult blood

A variety of tests and screenings are used to detect blood in stool. Today, laboratories use the 2 most informative methods to detect occult blood:

Immunochemical test. Such diagnostics are usually prescribed to identify pathological processes in the lower parts of the digestive system. The reaction occurs only in the presence of human hemoglobin, so it makes no sense for patients to adhere to any dietary restrictions, for example, to refuse to eat meat and iron-rich foods before diagnosis. Such a diagnosis is more convenient and is usually used as a screening procedure for the subject.
Gregersen reaction or benzidine test. This test is performed chemically and is used to detect bleeding in all structures of the gastrointestinal tract. Such testing is sensitive not only to human hemoglobin, but also to animal sources of iron, so a strict diet that excludes the consumption of meat products is necessary before diagnosis.

An immunochemical test for occult blood is considered the most informative; however, it is not able to detect bleeding when it is localized in the stomach or esophagus.

Only a specialist decides which research method is most appropriate in the case of a particular patient, so you need to contact a doctor with this question, and only then go to the laboratory to take a sample.

Indications

Typically, the need for analysis arises when there are suspicious symptoms such as:

Painful syndrome in the abdominal area;
Frequent diarrhea and constantly liquefied stool;
Dyspeptic symptoms such as nausea, bloating or heartburn, disturbing for a long time;
Various digestive disorders;
Sudden causeless weight loss;
Clinical examination of stool does not show bleeding.

In addition, test screening for occult blood is carried out in case of suspicion of the presence of colorectal oncology, anemia of unknown etiology, to detect intestinal bleeding and for preventive purposes in patients over 50.

If they are visible without any instruments or research, then this indicates their abundance. An experienced gastroenterologist can determine by the shade of stool where the bleeding focus is located.

If there are bright spots of blood in the stool, this indicates damage to the rectum or large intestine. If the stool has a black tint, the causes of bleeding should be looked for in the stomach or tissues of the esophagus.

Preparation

For maximum reliability of the test for occult blood, it is necessary to properly prepare for the diagnosis.

The main requirement for patients undergoing testing for the Gregersen reaction is to follow dietary recommendations.

Why do you need to exclude fish and meat dishes, seafood, alcohol, vitamin supplements and taking medications containing iron, which have an analgesic and anti-inflammatory effect, several days before the study?

In the latter case, the ban is due to the presence of ibuprofen or aspirin in these drugs. Also, the purpose of the diet is to normalize stool so that it becomes natural without the use of any drugs that may distort the result.

Ladies during menstruation should approach such a study with special care, because if menstrual fluid penetrates into the feces, the reaction will show an incorrect result.

About a week before the study, you should stop using rectal suppositories, oil compresses or microenemas.

You need to be especially careful when brushing your teeth so as not to damage the gums, otherwise blood may penetrate the gastrointestinal tract and appear in the samples during the study, which will lead to an erroneous result.

How to assemble?

The collection of biomaterial is also important for reliability. The feces intended for analysis should not contain any foreign impurities such as urine, water, secretions, etc.

Therefore, it is better to purchase a sterile container from a pharmacy for feces. The potty or vessel will also need to be disinfected. You cannot collect feces from the toilet.

Only natural stool without enemas or laxatives is suitable for the laboratory sample. Urine should not get into the container with feces.

Using a special spoon, you need to transfer the biomaterial into a container. By volume, feces should occupy at least 1/3 of the container. It is better to put several different fractions of feces, then the result will be more accurate.

How to submit?

After collecting stool, you need to send it to the laboratory as soon as possible; the maximum possible storage time is 3 hours.

There is no need to preserve or freeze stool; such samples are not suitable for diagnosis.

If stool has been collected, but it is not possible to deliver it to the laboratory right now, then you can place it in a refrigerator. But storing the sample for more than 3 hours is unacceptable.

What does the study show?

Therefore, any method for detecting rectal blood will show its presence. This is a consequence of natural processes, so doctors do not react to such indicators, paying attention only to higher indicators.

The intensity of the reaction is shown by the number of plus signs. If the result is weakly positive, then the analysis is assessed with one plus sign - “+”, a strongly positive result looks like “++++”.

Negative test results are the norm, but such data do not always indicate the absence of hidden internal bleeding. Sometimes bleeding is periodic, so it is not always detected during test screening.

When is the result positive?

If the result is positive, the doctor concludes that there is much more blood in the stool than is allowed naturally. And this may indicate the development of pathologies such as:

Infectious processes provoked by Koch's bacillus;
Inflammatory lesions of the duodenum or;
Tuberculosis;
Periodontal disease or stomatitis, gum bleeding or periodontitis;
Ulcerative colitis;
Cracks in the intestine;
Acute inflammation of hemorrhoids;
Varicose veins or thrombophlebitis of the esophagus;
Nasopharyngeal bleeding.

Also, hidden fecal blood can be a consequence of nasopharyngeal or throat pathologies. Gum bleeding, vasodilatation in the nose and resulting bleeding can all lead to rectal occult blood.

If a patient has a positive reaction to fecal blood, then he is usually prescribed a second diagnosis, because no one has canceled the false results. After all, not all patients approach preparation responsibly, violating the doctor’s recommendations.

How long does the examination take?

Results in the laboratory are prepared within several days, usually 3-6 days. The exact time of diagnosis depends on the specific laboratory.

Price

The average cost of diagnostics for occult rectal blood is about 240-900 rubles, which depends on the specific technique and laboratory.

For convenience, today pharmacies have home tests that operate on the immunochromatographic principle and react to human hemoglobin in stool.

The cost of such a test system is about 250 rubles, and the reliability is more than 99%.

Fecal hemoglobin analysis is a very common diagnostic test that allows early detection of dangerous pathological conditions, including oncology. As a result, the patient receives timely treatment, which maximizes the chances of a final recovery.

Video about fecal occult blood testing:

Particular attention is required when preparing for a stool occult blood test, since if it is absent or performed incorrectly, false positive results may be obtained.

regular diarrhea;
unexplained weight loss.

Types of tests

immunochemical test.

Enema is prohibited.

potato;
bread;

Collection of stool for research

False results

Diet before occult blood test

Indications for occult blood testing

Indications for taking an occult blood test are:

· stomach ulcer;

· nonspecific ulcerative colitis;

The patient is prescribed a three-day diet before the occult blood test. She excludes fish and meat, liver, green vegetables, white beans, spinach, pomegranates, apples, bell peppers, beets, horseradish, tomatoes and blueberries from her diet. At the same time, the diet before an occult blood test includes potatoes, cereals, dairy products, boiled eggs, butter, bread, and a small amount of fresh fruit.

Before testing feces for occult blood, the diet excludes not only the consumption of certain foods, but also the use of medications containing iron. These drugs include: bismuth and barium sulfate. They can affect the color of stool.

Also, before testing feces for occult blood, the diet, in addition to limiting certain foods, prohibits the use of laxatives, rectal suppositories and drugs that affect intestinal motility.

Two days before the test, it is not advisable to brush your teeth with a toothbrush, as this can damage the gums and blood from the mouth will enter the stomach.

Women are not tested for occult blood during menstruation.

You should not give an enema on the eve of the test, as it can damage the mucous membrane and lead to incorrect results.

Mixing urine with feces is unacceptable.

Following a diet before an occult blood test and following all the recommendations described above can guarantee accurate test results.

Procedure for taking a stool occult blood test

The collection of material for analysis occurs in the same way as for a general analysis of stool. A glass or plastic container or a special container is used as a container.

Stool collection is carried out from four places of fresh feces, excluding urine from entering them. To obtain the most accurate results, it is necessary to deliver stool to the laboratory within three hours after defecation.

More precise recommendations that are important for the diagnosis of a specific disease can be given by the attending physician. A similar analysis can be taken at a medical institution at your place of residence. In addition, you can take a stool test for occult blood in numerous medical centers and private laboratories at any convenient time. Test results will be ready within six days. The normal result of a stool occult blood test is negative.

Can the test result be false?

It happens that the analysis gives a false result. Most often, when the occult blood diet is not followed, or there is bleeding localized in the gums, a false positive test result is observed. Thus, strict adherence to the occult blood diet is a prerequisite before taking the test.

False negative test results are also possible. This happens in cases where the bleeding is not constant, but is periodically renewed.

In general, the sample is quite reliable, but to confirm the results, tests must be taken twice. If all the conditions are met before donating stool for occult blood, the diet is followed, samples are taken at intervals of 3-4 days, and the test result turns out to be the same, then it is reliable.

Positive test result

When the occult blood diet is followed, all the conditions for preparing for the test are met, and the test result is positive, this may indicate an ulcerative, oncological or inflammatory process. A positive test is a serious reason for diagnosis. If the doctor has written a referral for an occult blood test, the diet before taking it must be strictly followed.

For timely diagnosis and to avoid aggravation of the disease, the test must be completed at the first request in compliance with the required preparation. The sooner a correct diagnosis is made, the sooner it is possible to prescribe effective treatment.

Quantitative immunochemical test

Today, there is a relatively new method for determining occult blood - a quantitative immunochemical test. It is used in the diagnosis of colorectal cancer. Preparation for the test is minimal. To determine occult blood, you simply need to take a stool test, and there is no need to follow a diet.

A diet is not needed for the reason that this study uses antibodies to hemoglobin. Such antibodies do not react to myoglobin contained in eaten animal meat. The test is specific, characterized by high sensitivity and accuracy. The absence of the need to follow a diet makes this method very convenient for patients.

An occult blood test makes it possible to diagnose a number of diseases even before they cause irreparable harm to the body.

If your stomach hurts persistently and does not stop longer than usual, do not delay and go to the hospital, you may need to do a stool test for occult blood! It is necessary to determine the causes of pain as early as possible in order to avoid any complications and the possible development of diseases of the gastrointestinal tract and genitourinary system.

It is also possible that after a bowel movement you notice the presence of blood in the stool.

When is a stool occult blood test prescribed?

At the doctor's appointment, the abdominal cavity and the internal organs located in it will be examined. After the examination, the doctor, having made certain conclusions, may prescribe further diagnostics. Fecal occult blood testing is an important procedure for establishing an accurate diagnosis.

This test is prescribed if the doctor suspects bleeding in one of the parts of the digestive tract. Analysis is prescribed if the following factors occur:

prolonged abdominal pain, nausea, heartburn, vomiting;
with constant loose stools, false urge to defecate, lack of appetite and weight loss, increased body temperature;
in case of detection of tumors in the gastrointestinal tract;
in case of detection of worms;
if you previously had a stomach ulcer.

With intense bleeding in any part of the gastrointestinal tract, the blood changes the appearance of the stool quite significantly, which becomes noticeable to the naked eye. If bleeding occurs in the upper sections, the stool becomes black and tar-like due to the interaction of the blood with local enzymes.

Why is research needed?

If there is a suspicion of bleeding in any part of the gastrointestinal tract, doctors immediately prescribe stool tests to the patient.

Quite often, bleeding can be determined visually by the presence of blood in the vomit or stool. In this case, immediate action should be taken. It is worth noting that this may not always indicate internal bleeding. Nosebleeds and bleeding gums can have a similar effect.

In most cases, internal bleeding in the organs of the gastrointestinal tract may be intermittent and light, traces of it will not be noticeable in the stool. If the doctor suspects its presence, he will prescribe a stool test for occult blood.

This test is designed to detect changes in hemoglobin in red blood cells. The study is effective even when the bleeding is so weak that red blood cells are simply not visible under a microscope.

Changes in hemoglobin are detected through the interaction of the test stool and special chemicals (reagents), which change their color as a result of the reaction.

Sometimes an enzyme immunoassay of the material (stool) is performed to detect occult blood.

A stool occult blood test allows you to:

diagnose the presence and degree of development of diseases of the gastrointestinal tract
determine the nature and extent of damage to the mucous membrane of the tract.

Preparing for analysis

If a patient has been scheduled for a stool occult blood test, he or she must follow certain instructions.

It is necessary to start preparing for an occult blood test not two days in advance, but at least a week in advance.

About ten days before collecting stool, you should stop taking aspirin, non-steroidal anti-inflammatory drugs and other analgesics. It is worth stopping taking various laxatives and medications that contain bismuth and iron.

It is important to note that if the patient was prescribed a diagnosis using x-rays, then stool collection should be carried out at least two to three days after the x-ray.

What can you eat before the test?

Before taking an occult blood test, following a special diet is a very important procedure, the implementation of which directly affects the accuracy and reliability of its result. Maintaining the required balance of fats, proteins and carbohydrates in food will help you get the right conclusion.

According to Schmidt, it involves the consumption of dairy products.

How many days does it take?

Preparation for analysis may take about a week. This is exactly the time that the patient needs to follow all the necessary instructions to obtain the most accurate results of a stool occult blood test. Therefore, it is necessary to approach this issue as responsibly as possible, since this is in the interests of the patient himself.

How to assemble a chair correctly?

The collection of the material necessary for analysis - feces - must be carried out in compliance with certain nuances. This also affects the quality of the analysis result.

The most important thing is that bowel movements should be spontaneous. It is contraindicated to push and make efforts to speed up the emptying process. Moreover, the use of laxatives in any form, both medicinal and traditional, is contraindicated.

It is important to take into account that feces are collected from various parts of the feces. Do not allow urine and feces to mix.

If possible, collected stool should be delivered to the laboratory for analysis no later than three hours later. It should be stored in the refrigerator at a temperature of four to six degrees.

Analysis results

After the stool is collected, the patient takes it to the laboratory to be tested for hidden bleeding. Analysis results can be ready the next day.

The result of the obtained stool analysis for hidden bleeding determines all further actions of both the patient and the doctor.

A negative test result is considered normal. This means that there is no bleeding in the gastrointestinal tract. It shows that feces contain substances that the stomach is not able to digest.

The problem with stool testing for hidden bleeding is that it cannot always show the presence of polyps in the intestines. If the doctor has suspicions about this, he may prescribe additional diagnostics.

A positive result means that bleeding is present in the gastrointestinal tract. The reasons for this result may be:

intestinal tuberculosis;
stomach ulcer;
duodenal ulcer;
oncology of the intestines, stomach, esophagus;
nonspecific ulcerative colitis;
haemorrhoids;
worms (can scratch the intestinal walls);
colorectal cancer;
erosive esophagitis (inflammation of the esophagus affecting its mucous membrane).

It is worth considering that the result of a stool occult blood test may be false positive. The reasons for this may be nosebleeds and dental bleeding. In women, the presence of blood in the stool can be caused by radiation after cancer of the genital organs, or vaginal varicose veins in the last days of pregnancy.

Quite often, the result of this examination is false positive due to non-compliance with the rules and instructions for its preparation.

Where is the best place to do the analysis?

In most cases, a stool occult blood test is prescribed directly by the attending physician. That is why it is done in the clinic where the patient is registered. The test can be taken at various medical centers. For the convenience of the patient, a blood test for hidden bleeding can be done in a specialized laboratory at any time convenient for him. Many people take several tests simultaneously to different laboratories to obtain a more accurate and reliable result.

The price of the test varies depending on the medical institution where you do it. Taking the test at the clinic at your place of registration is absolutely free.

You will only have to spend money on a plastic container for collecting biological material. Tests in medical centers and laboratories are paid. The average price is about 130 hryvnia in Ukraine and rubles in Russia.

Reviews

Nikolai, 33 years old.

I suffered for a long time with my intestines. I tested stool for occult blood. It turned out that I had intestinal tuberculosis. I’m undergoing treatment now, but at least I know what it’s from.

I had a whole story with this examination. I did it several times, and several times it was positive. Then it turned out that during menstruation it is contraindicated to donate stool for blood testing.

Feces for occult blood: preparation, diet, interpretation of results

Collection of stool for occult blood: indications

The reason for the analysis may be:

Severe intestinal diseases;
Ulcer;
Colitis;
Polyps;
Anemia;
Poor appetite;
Abnormal stool;
A sharp change in weight downwards;
Frequent constipation;
Heartburn;
Acute pain in the abdominal area;
Constant nausea.

In addition, feces for occult blood are taken if there is a suspicion of cancer or a benign neoplasm.

You can get a referral for analysis from a surgeon, therapist, oncologist or gastroenterologist.

What do you need to know about the study?

At the present stage, everyone who undergoes an occult blood test needs to have at least general information on this matter.

The fresher the sample, the more accurate the results will be.

Before taking samples, simple preparation is required for several days.

By the form you can understand whether there are deviations in the functioning of the intestines. In a healthy person, stool is sausage-shaped, medium-density, brown in color. If abnormal, excrement can be very dense or liquid, lumps or in the form of a ribbon. In severe pathologies, not only the appearance changes, but also the composition, smell, and various impurities appear.

Normal feces may contain particles of undigested food - the norm is the peel of fruits or vegetables, cartilage or tendons.

If mucus or blood is visible to the naked eye, this indicates a disease of the colon.

Collect the sample in a special jar-container with a spoon; it must be purchased in advance. To make an accurate analysis, a few grams of material is enough.

The last rule applies to women. It is not recommended to take material during menstruation, as blood can get into the excrement and spoil the results.

Diet before stool occult blood test

A few days before the samples are taken, a special diet is prescribed, which must be followed in order for the analysis to be correct the first time.

During this period you should not eat:

Liver in any form;
Legumes;
Fish and meat dishes;
Apples and other fruits that affect the color of feces;
Greens, particularly spinach;
Some vegetables: tomatoes, sweet peppers, beets, hot horseradish.

Sample menu for one day:

Bread and butter, milk soup, some pears or peaches, canned in winter;
Mashed potatoes, 2 boiled eggs, milk jelly;
Yogurt without dye;
A glass of kefir or fruit.

The amount of food taken at one time should not exceed 1 gram. The same set of foods with some corrections and variations should be eaten for another 2 days.

Feces for occult blood: interpretation

Fecal occult blood test: preparation, price

A stool occult blood test can detect traces of blood that are not visible during microscopic examination.

An occult blood test can detect bleeding from any part of the gastrointestinal tract.

Indications for analysis: suspicion of the presence of bleeding in any part of the gastrointestinal tract.

Preparing for a stool occult blood test

A few days (about a week) before taking a stool test, you must stop taking medications (especially iron, bismuth, laxatives).

You should not give an enema the day before the test.

After an X-ray examination of the intestines and stomach, it is not recommended to prescribe stool tests earlier than two days later.

Diet required before taking a stool occult blood test

Three days before taking a stool test, the following should be excluded from your usual diet:

liver;
meat;
foods that contain iron (green onions, white beans, spinach, bell peppers, apples).

To properly perform a stool occult blood test, you should empty your bowels yourself into a plastic, disposable, airtight container with a tight-fitting lid.

Do not allow urine to be mixed with feces.

Before sending the analysis to the laboratory, the prepared material must be refrigerated at an average temperature of about 5 degrees Celsius. The container with stool should be delivered to the diagnostic laboratory on the same day that the material was collected.

The stool analysis takes six full working days to prepare.

The normal value for a stool occult blood test is negative.

Determination of occult blood in stool

To determine occult blood in stool, the method of immunochromatography is used.

The deadline for completion is one day.

The immunochromatography method is prescribed to patients to determine human intact transferrin and hemoglobin in order to detect hidden intestinal bleeding.

Immunography is prescribed to patients for:

diagnosis and detection of diseases of the duodenum and stomach;
Crohn's disease;
neoplasms of the large intestine (polyps, cancer).

sensitivity and specificity of the test – more than 99%;
absence of cross-reactions with transferrin and hemoglobin of animal origin (meat may not be excluded from the daily diet);
In addition to identifying hidden intestinal bleeding, it is possible to clarify damage to the gastrointestinal tract (lower and upper sections).

It is not allowed to take a stool test for hidden bleeding:

after strong straining during defecation;
hematuria;
bleeding from hemorrhoids;
menses.

In Moscow, the cost of stool tests for occult blood is 300 (three hundred) rubles.

Fecal occult blood test

Causes of blood in stool

The main and most common cause of occult blood in the stool is tumor processes in the intestines (colorectal cancer). Hidden blood in stool is that which is not visible visually or even under a microscope. It is known that intestinal tumors bleed. There is a small amount of this blood in the initial stages of the disease. Once in the intestinal lumen, red blood cells and along with them hemoglobin are destroyed by digestive enzymes and therefore become invisible.

In addition to colorectal cancer, the causes of the appearance of occult blood in the stool of an adult can be polyps in the intestines, any inflammatory process, ulcerative process in the intestines, diverticulosis (pockets in the intestines), Crohn's disease, ulcerative colitis (UC).

Why is research needed?

A stool occult blood test shows the presence of invisible hemoglobin and red blood cells. The study is very valuable in determining intestinal bleeding in the early stages, when it is not yet visible to the eye. In what cases is a stool test for occult blood indicated? Below are the main factors:

Pain or discomfort during or before bowel movements.
Any impurities in stool (mucus, foam).
Changes in stool character. It has become liquid or, on the contrary, too dense.
Traces of blood are periodically visible in the stool.
Decreased appetite or significant weight loss.
Abdominal pain of any location.
The presence of symptoms such as heartburn, nausea, vomiting, iron taste in the mouth.
Periodic causeless increase in body temperature.
Annually as a screening examination for patients over 40 years of age. It is carried out for the early detection of colon tumors.

If you have any of the above symptoms, it is recommended to have your stool tested for occult blood.

Preparing for a stool occult blood test, what is it for?

Patient preparation is necessary only in case of analysis by chemical reactions (benzidine, guaiac tests). These tests often give false positive reactions, for example to animal hemoglobin found in meat foods, or to chemicals in food and vitamins.

It should be borne in mind that the analysis is reliable only for bleeding from the lower intestines (colon and rectum). In the upper sections, hemoglobin is significantly affected by digestive enzymes and is destroyed. Therefore, after the study, if the result is positive, it is recommended to undergo additional examination (colonoscopy, for example).

How to prepare for the analysis?

Diet before stool occult blood test. For three days (72 hours) you need to exclude food of animal origin (meat, fish) from your diet. You should also exclude some vegetables, especially green ones: cauliflower, cucumber, horseradish, green apples, spinach, lettuce, any greens and zucchini. Tomatoes are also excluded.
The use of iron-containing medications, bismuth and barium sulfate is not recommended. Also, on the eve of the test, you should not take acetisalicylic acid (aspirin) and ascorbic acid (vitamin C).
Three days before the study, it is not recommended to carry out any diagnostic or therapeutic manipulations with the intestines (x-ray contrast study, sigmoidoscopy, colonoscopy).
You should not use laxatives or give enemas. Material for analysis is collected after three spontaneous bowel movements from different areas of the stool.
This test is not recommended for menstruating women.

How to get tested correctly?

For a reliable result, after proper preparation, you need to collect the feces in a specially designed container purchased at the pharmacy. The material should be taken after natural emptying from several areas of stool. The amount of material is sufficient in the amount of 1 teaspoon.

Decoding the analysis results

A positive test reaction indicates processes in the intestine that lead to a violation of the integrity of its mucous membrane. This means that red blood cells and hemoglobin enter the intestinal lumen. But you should not rely only on the results of one analysis. A number of diseases of the intestines and other organs can give a positive reaction. For example, nosebleeds, stomach polyps, ulcerative lesions of the esophagus, hemorrhoids and even helminths. To make an accurate diagnosis, a complete examination of the patient is necessary.

The test result may also be false positive if a reaction occurs not to human hemoglobin, but to substances or dyes contained in food. This usually happens when the patient is incorrectly or insufficiently prepared for the study. In any case, a positive result is a reason for a more in-depth examination of the patient.

A negative test result is the norm for a person. But this result does not always indicate the absence of intestinal bleeding and should not reassure either the patient or the doctor. A negative result has no diagnostic value. For greater reliability, if the result is negative, the analysis can be repeated three times.

If you are concerned:

abdominal pain, nausea or vomiting;
heartburn;
bowel disorders, alternating with constipation;
mood swings;

Preparing for a stool occult blood test: diet before taking the test, how to take it

Examination of feces for occult blood is one of the laboratory tests that makes it possible with a high degree of probability to diagnose internal bleeding in one of the sections of the gastrointestinal tract. Particular attention is required when preparing for a stool occult blood test, since if it is absent or performed incorrectly, false positive results may be obtained.

Indications for the purpose of analysis

Examination of stool for blood hidden in it is prescribed for the following patient complaints:

Constant/recurrent abdominal pain;
frequent symptoms of dyspeptic disorder - nausea, vomiting, heartburn;
regular diarrhea;
unexplained weight loss.

Types of tests

The study is performed in two ways:

Gregersen method (benzidine test);
immunochemical test.

The Gregersen test is quite informative, but only if the patient has thoroughly prepared

Preparing for the Gregersen test

To get the most reliable results, you need to properly prepare for stool donation. The recommendations will be as follows:

A week before the planned delivery, it is necessary to stop taking medications such as laxatives, bismuth- and iron-containing drugs, and non-steroidal anti-inflammatory drugs. It is prohibited to use acetylsalicylic acid and medications containing it.
It is necessary to avoid administering rectal suppositories.
Enema is prohibited.
Before testing stool for occult blood - two days before the test - you need to exclude any instrumental tests of the gastrointestinal tract. During the study, the mucous membrane may be accidentally damaged. Released blood may cause false positive results.
A few days before collecting excrement, you should stop brushing your teeth. Even a small amount of blood released when the gums are damaged can enter the stomach. And this hemoglobin can also negatively affect the final result.

The main point of preparing for the test is strict adherence to the diet.

The patient's diet should completely exclude foods high in iron. The collection of stool must be preceded by refusal:

Ideally, in order not to make a mistake with the menu, doctors recommend adhering to a dairy diet during the days of preparation for donating stool. The diet may also include:

potato;
bread;
porridge (with the exception of buckwheat, oatmeal, egg, lentils, peas).

Collection of stool for research

Even careful preparation will be completely useless if the biological material is collected incorrectly.

There are special containers for transporting feces to the laboratory - they are sterile and guarantee the biological purity of the collected excrement

How to pass feces correctly? To obtain material suitable for research, you must follow the following recommendations:

A sterile container must be used to collect excrement. It can be purchased at any pharmacy. The set includes a jar with a lid and a special spoon.
First you need to empty your bladder. Then place an oilcloth in the toilet.
After bowel movements, it is necessary to take three portions of feces from different places.

The material must be delivered to the laboratory within the next three hours. It cannot be stored.

False results

Failure to follow the preparation rules before donating stool may result in erroneous results. They can be either false positive or false negative.

The main reason for false-positive tests indicating the presence of internal bleeding is improper preparation.

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Today, there are many ways to diagnose the body and study various biomaterials. To diagnose internal organs and the condition of the gastrointestinal tract, feces are taken for occult blood. Preparation for such an analysis is simply necessary, since improper nutrition can distort the result.

Blood in the stool is a sign of gastrointestinal pathology

For the normal functioning of all internal organs, it is necessary to carry out diagnostics and tests from time to time so that it is possible to determine the disease at the initial stage. The condition of internal organs cannot be examined in any way without resorting to special equipment and analysis methods.

A stool test to detect hidden blood in the body shows the presence or absence of internal bleeding in the gastrointestinal tract. Diagnostics can show the development of many diseases associated with disruption of the digestive system. Blood occurs from wounds, ulcers and microcracks. When diagnosed using visual equipment, such damage is not visible, which is why there is a need for stool analysis.

In normal health, no more than 2 ml of blood is passed through the stool every day.

This is considered the norm. If there is more of it, this fact indicates internal bleeding, which can be evidence of many diseases - colitis, ulcers, tumors and other gastrointestinal pathologies.

A doctor prescribes a test to detect hidden blood in the stool in the following cases:

suspected ulcerative colitis
diagnosis of colorectal cancer
anemia (anemia)
diagnosis of intestinal bleeding
preventive diagnostics for people over 50 years of age

When the doctor writes a referral, he provides a consultation on how to properly prepare for the occult blood test.

Heavy internal bleeding is visible to the naked eye. They change the color and consistency of stool. Color specialists can determine which organ is affected. Brightly colored blood spots indicate problems in the colon or rectum. If the stool turns almost black, this is a sign of problems in the stomach or esophagus.

Preparing for analysis

Feces for analysis must be collected in a special sterile container!

In order for the analysis result to be as accurate as possible, you need to properly prepare for the analysis. First of all, a few days before the test you need to follow a special diet. It is necessary to completely eradicate meat and fish, vitamin complex and medications, alcohol, and seafood from the diet.

The analysis is carried out in several ways. The most common is the benzidine test (Gregersen reaction). It gives a reaction not only to human hemoglobin, but also to proteins of animal origin, so consuming meat dishes on the eve of tests may result in false data.

Diagnosis using the immunochemical method does not require a special diet, but you should still avoid meat and fish a few days before the tests. It is also necessary to abandon medications that have anti-inflammatory and analgesic effects. They usually contain ibuprofen, acetylsalicylic acid, and medications containing iron. Also, the stool should be natural, without the help of an enema or laxatives. Otherwise, an admixture of medicinal substances may cause an incorrect result.

More information about fecal occult blood testing can be found in the video:

You need to be very careful when giving stool to women during menstruation. If blood gets into the stool, the result will be false. When it is necessary to take a stool test from an inpatient patient, they are warned about this in advance in order to exclude the use of suppositories, enemas, Vaseline and other drugs.

The test result can be positive or negative

A positive result means that the stool contains more blood than expected. This indicates one or more diseases:

stomach ulcer, inflammation of the duodenum
infections caused by Koch's bacillus
ulcerative colitis
stomach cancer
thrombophlebitis and esophageal varices
stomatitis, periodontal disease, periodontitis, bleeding from the gums
nasopharyngeal bleeding

In addition to diseases of the gastrointestinal tract, hidden blood in stool can be caused by diseases of the nose or throat. Bleeding gums, dilated blood vessels and nosebleeds are also causes of occult blood. Hemorrhoids and anal fissures are a common cause of blood in the stool.

If the result is positive, it is necessary to schedule a repeat diagnosis, because the possibility of a false result due to improper preparation for stool donation cannot be ruled out.

In addition to fecal occult blood testing, other diagnostic methods are also used to identify a particular disease.

In the end, it is important to note that it is necessary to take tests at least once a year for the purpose of prevention. Internal bleeding may not cause symptoms or bother a person for a long time, although the disease develops. An analysis for occult blood in stool allows you to identify many pathologies and provide timely assistance. As a rule, the blood rate increases in case of vascular diseases (blood clots, varicose veins) or gastrointestinal tract (ulcers, colitis, cancer, etc.) for reliability, it is recommended to repeat the analysis over time, since the possibility of false data is not excluded.

How to donate and what does a stool occult blood test show?

Blood during bowel movements may indicate a serious illness, ranging from an anal fissure to a malignant neoplasm in the digestive organs.

However, in the early stages, the pathology often develops without obvious symptoms, and hidden bleeding can be difficult to notice.

A stool occult blood test detects the smallest impurities of blood and allows you to diagnose diseases in the initial phases, which is extremely important if cancer is suspected.

In what cases is it prescribed?

A stool occult blood test is prescribed for the following symptoms:

Stomach ache;
Dyspeptic symptoms (heartburn, bloating, nausea) for a long time;
Frequent diarrhea, constantly thin stool;
Other digestive disorders;
Sudden weight loss for no apparent reason;
Clinical stool analysis does not show the presence of bleeding.

The presence of occult blood must be checked if inflammation of the gastrointestinal tract, peptic ulcer, or neoplasm is suspected.

Research methods

Modern laboratories use 2 main analysis methods:

The Gregersen test, as a chemical test for occult blood is called, is used to detect bleeding in all parts of the gastrointestinal tract. The test is sensitive to hemoglobin of both humans and animals, so special preparation and a meat-free diet are required before taking it.
A stool occult blood test using an immunochemical method is prescribed to diagnose pathologies of the lower part of the digestive tract. The test only tests human hemoglobin, so patients do not need to limit their diets to meat and iron-rich foods. A stool occult blood test without diet is more convenient and is widely used as a screening test for colorectal cancer.

Immunochemical analysis is considered more modern and sensitive, but it is not informative regarding bleeding in the esophagus and stomach.

The choice of method is made by the doctor, depending on the patient’s complaints. Before going to the laboratory, consult a specialist!

How to prepare?

Patient preparation depends on the chosen research technique.

Taking a stool occult blood test using the immunochemical method does not require changes in diet.

2 weeks before it you should refuse:

From drugs that increase the risk of bleeding (aspirin, ibuprofen).
From laxatives.
From procedures that can damage the mucous membranes of the gastrointestinal tract (enemas, colonoscopy, etc.).

When testing for fecal blood, the diet excludes:

The diet should begin 3 to 4 days before the study, in addition, during this period you should:

Avoid taking medications, foods, and drinks that can stain stool and affect intestinal motility;
Avoid enzymes;
Do not use rectal suppositories;
Postpone x-ray examination of the gastrointestinal tract;
Replace brushing with hygienic rinsing to prevent damage to the gums and blood from entering the esophagus from the oral cavity;
Women do not test fecal occult blood during menstruation and 3 days before and after it.

How to assemble?

Proper preparation and delivery of the analysis affect the reliability of its results.

In no case should foreign impurities enter the test material: water, urine, genital secretions, X-ray contrast compounds, suppository components, etc.

How to prepare for stool collection:

Purchase a sterile container. It is a container with a screw cap and a spoon. Containers are sold in pharmacies and laboratories.
Disinfect the vessel, pot, or other container suitable for defecation. Wash with soap, rinse several times with clean water, and pour over boiling water. You cannot collect feces from the toilet.

Only natural feces are suitable for research, without laxatives or enemas.
You should defecate in a prepared container, avoiding urine.
Use a special spoon to take the feces and transfer the material into a container.
Close the lid.
Attach a stool occult blood test form issued by the laboratory or prescribed by a doctor to the container.

How to submit?

Prepared feces cannot be stored; only fresh material that has not been frozen or preserved is suitable for analysis.

The result of a stool occult blood test is prepared within a few days. Typically, the study period is 3–6 days, depending on how long the analysis is done in a particular laboratory.

Analysis results

The intensity of the reaction is expressed by the number of “pluses”: from one – weakly positive, to four.

The Gregersen occult blood test may show:

Erosive gastroduodenitis;
Exacerbation of ulcers;
Tumor in the stomach, intestines;
Diverticulum;
Varicose veins of the esophagus;
Haemorrhoids;
Intestinal tuberculosis;
Crohn's disease;
Polyps;
Nonspecific ulcerative colitis.

With the chemical research method, there may be other reasons for hidden blood in stool analysis that are not related to gastrointestinal diseases.

What the immunochemical method shows: a result >50 ng/ml indicates hemorrhoids, polyps, colorectal carcinoma, ulcerative colitis or Crohn's disease.

A physician should interpret laboratory results. If the test for occult blood in the stool is positive, additional diagnostic measures need to be carried out to clarify the pathology.

Where to do it?

Having received a referral for testing, the patient himself has the right to choose where to donate stool for hidden blood: in a public clinic or a private laboratory (Invitro, Helix and others).

The price of the service is in the range of 350 – 700 rubles, depending on the technique used.

An immunochromatographic stool occult blood test has been developed for use at home. This is a quick and simple tablet test that detects human hemoglobin cells in feces.

How to do the analysis yourself:

Purchase a test at the pharmacy to diagnose hemoglobin in human stool;
Open the package;
Collect feces with a special applicator into a container with a reagent;
Place 2 drops of liquid onto the indicator tablet;
Wait for the result.

Every adult knows that if blood appears in the stool, this is a symptom of a disease that can be life-threatening. If such a pathology is detected, you should immediately consult a doctor. There are many diagnostic methods that detect hidden bleeding, one of which is stool analysis.

Why donate stool for occult blood?

Some diseases of the digestive system are asymptomatic in the first stages. However, blood particles can be detected in stool even at the beginning of the development of pathology through research. Their sizes are very small, so sometimes it is impossible to notice even under a microscope. At the slightest suspicion of the occurrence of certain diseases, doctors send the patient to take a stool test for occult blood. This test is carried out to detect bleeding from the following digestive organs:

liver;
intestines;
spleen;
stomach;
rectum.

How to properly prepare for the test

In order for the test for occult blood in the stool to be reliable, you should properly prepare for the test. First of all, on the eve of taking the material, you cannot do enemas, and the emptying process should be natural. Women during menstruation should refrain from testing. Before the procedure, you should not do any X-ray examinations for three to four days. On the eve of taking the test, it is forbidden to brush your teeth, because if the smallest blood particles enter the digestive tract from damaged gums, the results will be distorted.

Diet before stool occult blood test

Before the study, the patient is prescribed a three-day diet. Its essence is adding potatoes, butter, boiled eggs, dairy products, and cereals to the daily diet. In order for stool collection for occult blood to be effective, you must completely avoid the following products:

liver;
fish;
meat;
beet;
white beans;
horseradish;
green vegetables;
spinach;
tomatoes;
Bell pepper;
blueberry;
apples;
grenades.

Refusal to take medications

It is necessary to refuse not only certain foods before taking a stool test for occult blood, but also the use of medications that contain iron. These are barium sulfate and bismuth. They are able to color stool in a color that is unnecessary for analysis. Also, you should not take any laxatives that affect intestinal motility and acetylsalicylic acid (aspirin).

How to collect a stool test

Examination of feces for occult blood involves the collection of material, but no special recommendations are required. The kit is collected in a sterile container. Stool should be collected in the morning and delivered to the laboratory or diagnostic center no later than 3 hours after bowel movement. The adequacy of the final results depends on how correctly the preparation for the analysis was carried out. How to properly test stool for occult blood:

urinate in the morning so that the stool does not contain urine impurities;
perform thorough hygiene of the genitals;
collect stool using a bedpan;
Using a spatula, carefully transfer the material into a clean container.

How much stool is needed for analysis?

Once preparations for a stool occult blood test have been made, collecting material is not difficult. This laboratory test requires a very small amount of feces. In pharmacies you can buy special plastic containers for these purposes. Such a jar should be filled no more than a third (10-12 ml). If it is not possible to deliver the material to the laboratory immediately, then you can store it for a day in the refrigerator or a cold place at a temperature of +6 °C and below.

Stool examination

A large-scale task is performed by blood tests in relation to hidden bleeding in different parts of the gastrointestinal tract. To carry out the test, a special chemical reagent is used that reacts to the minimum level of hemoglobin, including in animal meat eaten the day before. Heavy bleeding is visible to the naked eye, because the color of the bowel movement changes radically. Scarlet blood characterizes the pathology of the colon or rectum. A tarry, black consistency indicates a problem in the esophagus, stomach or small intestine.

In smaller-scale disorders of the gastrointestinal mucosa, the color and consistency of the collected material does not change. The presence of red blood cells is determined through microscopic examination. To diagnose bleeding, screening tests are used to help identify asymptomatic diseases. Most clinics use a sensitive guaiac test. Its reactions to detect pathology work due to the property of hemoglobin to accelerate all oxidative processes.

During the analysis, feces are applied to special filtered paper, then guaiac reagent, hydrogen peroxide, and acetic acid are applied. If the hemoglobin concentration is less than 2 mg per 1 mg of stool, then the test result is negative. When the reaction to occult blood in the stool is positive, even small metastatic and primary tumors can cause it, so the blood sensitivity test is widely used to detect colon cancer.

Decoding the analysis results

If after the examination the reaction of the collected material is negative for occult blood, this means that the state of the gastrointestinal tract is normal. When a positive result is determined, this means that the patient has chronic pathologies accompanied by damage to the mucous membrane. This test result may indicate colitis, colon polyp, duodenal or stomach ulcer. Due to hemorrhoidal bleeding, severe straining during bowel movements, helminthic infestation or blood from the mouth, false positive results may be detected.