Typhoid fever test result. How to take a blood test for typhoid fever. How to get tested for salmonellosis

A diagnostic serological test for detecting antibodies to Vi-antigens of the typhoid pathogen in blood serum is intended to confirm or deny the fact of carriage.

General information about typhoid fever and its detection

Typhoid fever refers to acute infectious intestinal diseases. It is characterized by a cyclic course with systemic damage to the intestinal organs, central nervous system, liver, and lymphatic system; general intoxication of the body, persistent bacteremia, in which the presence of bacteria is detected in the blood. The source of infection is sick, recovered bacteria carriers.

The causative agent of typhoid fever - salmonella Salmonella typhi, refers to intestinal bacteria.

The antigenic system of the pathogen is represented by antigens O, H, Vi.

Vi antigen is a virulence antigen, forming the resistance of the typhoid Salmonella pathogen to the body’s protective reactions. The presence of antibodies to Vi-antigens of Salmonella typhi during serological testing of blood samples serves as a marker of bacterial carriage.

Blood test method with Vi-antigen

Antibodies to erythrocyte Vi antigens are detected using serological reaction of indirect hemagglutination, RNGA , using special diagnostics.

RNGA method:

• based on the ability of interaction between blood serum antibodies and antigens that are fixed on red blood cells (erythrocyte diagnosticum); the result of the reaction is aggregation of erythrocytes followed by sedimentation, agglutination;
• by the nature of the erythrocyte sediment, one judges the presence of antibodies (a characteristic “umbrella”) or their absence (a sediment in the form of a “dot”);
• is semi-quantitative; to carry out the reaction, dilutions of blood serum are used to determine the diagnostic titer;
• the minimum diagnostic titer during the reaction is 1:40;
• an increase in the diagnostic value of the reaction is observed when using repeated analysis (paired serum method);
• the reaction is highly sensitive and specific and can be used on the fifth to seventh days of the disease.

The main purpose of the study is to identify the carriage of typhoid Salmonella bacteria.

Analysis results and their interpretation

Test results may be positive or negative.

A positive response:

• detection of antibodies to Vi-antigens of the typhoid pathogen in the blood (minimum diagnostic titer value 1:40) is considered as an indication of the fact of bacterial carriage and the need for repeated testing;
• the response records the titer value;
• may indicate an acute infection, a previous illness, or vaccination;
• in rare cases it may be false positive due to cross-reaction.

Conducting this study is of particular importance to prevent the spread of typhoid fever by bacteria carriers.

Typhoid fever– an acute infectious disease that affects the intestines and its lymph nodes. The disease is accompanied by an enlarged liver and spleen, severe intoxication with high fever and clouding of consciousness.

Although the incidence of the disease has decreased over the past hundred years, the problem still remains very relevant. Every year, about 20 million people worldwide become infected with typhoid fever, and 800 thousand die from this disease. People get sick more often in developing countries, where there is a lack of drinking water, poor sanitation and street food trading flourishes. Therefore, tourists who travel to Central Asia, Africa or South America should be extremely careful.

It is especially dangerous to swim in bodies of water that may be contaminated with sewage and to buy ready-made meals in markets. The highest risk is associated with dairy and meat products, in which the bacteria begins to actively multiply at a temperature of +18 C.

In Russia, thanks to sanitary control, typhoid fever was almost completely eliminated. But in recent years a new danger has arisen. Migrants who come to work and our tourists bring Salmonella typhoid from other countries. One sick person can cause infection to many people, especially if he works in the food industry.

You can become infected with typhoid fever from a sick person and from a bacteria carrier who feels completely healthy. The route of transmission is fecal-oral. This means that the bacterium is released from the intestines of a sick person and enters the mouth of a healthy person through food, drinking water, dirty hands or household items.

Large outbreaks and epidemics occur in the summer-autumn period. At high temperatures, the typhoid bacillus multiplies quickly. In addition, flies contribute to its spread.

Sensitivity to the bacterium that causes typhoid fever is high and people of any age can become infected. But according to statistics, children and young people under 30 get sick more often. This is due to the fact that they are more active: they travel more often and eat outside the home.

The causative agent of typhoid fever

Typhoid fever is distinguished from other diseases by the following symptoms:

• heat
• skin pale and dry
• enlarged dry tongue, coated in the center and clean around the edges
• soreness and rumbling under the right rib
• slight rash in the form of red spots in the upper abdomen and lower chest (appears on day 8-9)
• reduction in heart rate at high temperatures
• signs of intoxication: weakness, lethargy, depression, lethargy, headache

General clinical tests

1. Hemogram or clinical (general) blood test. Determines the amount of all elements that make up blood. With typhoid fever the following changes appear:
   • moderate leukocytosis - in the first days of the disease, the number of leukocytes slightly increases and the ratio of their types changes. but over the course of a week their number decreases sharply.
   • leukopenia – low number of white blood cells
   • aneosinophilia – absence of eosinophils in the blood
   • relative lymphocytosis - an increase in the percentage of lymphocytes compared to all other leukocytes.
   • increased ESR - erythrocyte sedimentation rate increases, but not significantly
2. General urine analysis. Urine examination in the laboratory. A laboratory assistant studies the physicochemical characteristics and examines the sediment under a microscope. With typhoid fever, the following is found in the urine:
   • red blood cells
   • cylinders

For laboratory diagnostics, blood, urine, bile and feces are taken. They are inoculated on nutrient media and placed in a thermostat, where the temperature is constantly maintained at 37 C. If the tests contain typhoid bacteria, they form colonies that can be examined under a microscope. Bacteria in the blood can only be found in sick people, but in feces and urine, salmonella can be found in both a sick person and a carrier of the bacteria.

1. Hemoculture– isolation of Salmonella typhoid from the blood. This is the earliest and most accurate diagnostic method. Bacteria appear in the blood during the incubation period and remain until the end of the disease. To detect them, blood (10 ml) is taken from the antecubital vein and inoculated on Rappoport’s liquid nutrient medium. A preliminary result can be obtained on the second day, but the entire study lasts 4 days.


2. Coproculture– isolation of typhoid bacteria from feces. Salmonella is found in the intestinal contents from 8-10 days of illness. In this case, solid nutrient media are used.


3. Urine culture– determination of typhoid bacteria in urine. It is examined no earlier than on the 7-10th day of illness.


4. Bile culture– to study bile, a probe is inserted into the small intestine. Bile is collected in sterile tubes and cultured. This study is carried out after recovery.


5. Bone marrow culture– a sample is taken during a puncture in the second or third week of illness. It is performed if there is a suspicion that typhoid fever has severely damaged the bone marrow.

Serological research methods

Starting from the second week, special antigens appear in the blood. These are particles of the membrane and flagella of typhoid Salmonella. They can be identified using studies based on immune responses. For analysis, blood is taken from a finger and the serum is separated from it.

1. Vidal reaction– determines whether there are O- and H-antigens in the venous blood serum. After interacting with special substances, cells containing particles of typhoid bacteria stick together and precipitate. A positive result can occur not only in the patient, but also in a person who has recovered from the disease, a carrier, or after vaccination. To know for sure that bacteria are multiplying in the blood, the reaction is carried out several times. In case of illness, the titer (level) of antibodies is 1:200 and is constantly increasing.
2. Passive hemagglutination reaction (RPHA with cysteine)– the blood serum of a sick person sticks together (aglutenizes) red blood cells coated with antigens. This study also needs to be carried out several times to see if the antibody titer increases. In a sick person it is 1:40 and can increase 3 times. The first analysis is taken on day 5, and then as needed at intervals of 5 days. Vi- and H-antibodies may be elevated in convalescents and carriers.

Treatment of typhoid fever

Treatment of typhoid fever proceeds in several directions at once.

Fighting infection

For severe forms, a combination of antibiotics Ampicillin and Gentamicin is used. Or new generation drugs Azithromycin, Ciprofloxacin.

If antibiotics do not work or are poorly tolerated, then antimicrobial drugs of other groups are prescribed: Biseptol, Bactrim, Septrim, Cotrimoxazole. They are taken 2 tablets 2 times a day. Course 3-4 weeks.

Fighting intoxication and dehydration

In case of moderate condition, it is necessary to cleanse not only the intestines, but also the blood. To do this, glucose-saline solutions are administered intravenously so that toxins are eliminated faster by the kidneys. The drugs used are: Lactasol, Kvartasol, Acesol, 5% glucose solution. They are prescribed up to 1.5 liters per day.

If, despite all efforts, intoxication intensifies, then Prednisolone tablets are prescribed for 5 days.
Oxygen therapy helps fight intoxication well. Oxygen is administered through catheters into the nose or using a special oxygen pressure chamber.

If medications do not help, and the condition continues to worsen over three days, then a blood transfusion is given.

Improvement of general condition

The angioprotector Ascorutin helps improve the functioning of small capillaries, normalize metabolism and blood circulation.

Tincture of ginseng, Schisandra chinensis or eleutherococcus improves general condition, gives strength and increases the tone of the nervous system. Natural herbal preparations are used together with a complex of vitamins: A, B, C, E.

Diet for typhoid fever

After discharge from the hospital (6-7 weeks of illness), the menu can be gradually expanded. Do not immediately lean on prohibited smoked and fatty foods. Try small portions of new foods for 7-10 days.

Folk remedies to combat typhoid fever

To treat typhoid fever during epidemics, decoctions of black currant or rose hips, as well as coffee with lemon were often used.

Infusions of medicinal herbs help speed up the healing of ulcers in the intestines and cleanse the blood of toxins. Pour 1 tablespoon of burnet roots with a glass of hot water and boil for half an hour. Take a tablespoon every 2-3 hours.

Pour 1 tablespoon of St. John's wort herb with a glass of boiling water and leave in a thermos for 1 hour. Drink in small sips throughout the day.

Prepare a mixture of centaury, sage and chamomile herbs. Pour 1 tablespoon of the mixture into a glass of boiling water, leave for 30 minutes and strain. Drink a teaspoon 7-8 times a day.

Folk remedies can be an addition to the treatment prescribed by an infectious disease doctor. But remember, you should not try to overcome the disease on your own. During the treatment of typhoid fever, antibiotics are indispensable.

Dispensary observation

You can be discharged from the hospital no earlier than a month after the onset of the disease or 21 days after the temperature drops below 37 C. Before discharge, stool and urine samples are taken 3 times. If Salmonella typhoid fever is not detected in the discharge, they are sent home.

Typhoid fever has the insidious property of “returning.” This repeated development of the disease is called relapse. In order not to miss the new development of bacteria in the body and carriage, after discharge the patient will have to frequently communicate with doctors and undergo tests.

For the first two months, examinations are carried out once a week. 10 days after discharge you will need to test feces and urine 5 times with an interval of 1-2 days. In the future, you will be able to visit the clinic much less often. After 4 months, it is necessary to take a bile and blood test for the reaction of RPHA with cysteine. If the result is negative and no traces of bacteria are detected, the person will be removed from the register.

Prevention of typhoid fever

Inoculation or vaccine against typhoid fever

Who needs to be vaccinated?

Since children become infected more often, they need vaccination more often. Therefore, in areas where cases of the disease often occur (25 patients per 100,000 population), children aged 5-19 years are vaccinated. Vaccination is also recommended for people at risk. For example, family members where there is a patient and medical workers who encounter this infection.
In our country, general compulsory vaccination is carried out only during epidemics. In other cases, doctors recommend, but do not force, vaccination against typhoid fever.

In recent years, tourists who are planning to visit Asia, South America and Africa have also been vaccinated against typhoid fever. You may not be allowed into countries that are dangerous for typhoid fever without a vaccination certificate. You can clarify this issue with tour operators. The vaccination must be done no later than 1-2 weeks before departure so that immunity has time to form. It helps protect travelers and their families and prevent the spread of this disease in Russia.

How effective are typhoid fever vaccinations?

Efficiency varies slightly among different manufacturers, but is approximately the same. It is 60-75%. This does not mean that the vaccine has no effect at all on the remaining 25-40% of people. If they get sick, it is in a milder form.
Remember that the vaccine does not guarantee against infection. Therefore, even if you were vaccinated before your trip, you will still have to take precautions.

What vaccines are used?

Hygiene

But each of us must take care of our own health. Especially in countries where typhoid fever is common. Follow basic safety rules:

• drink only store-bought water
• don't buy food on the streets
• if there is no other choice, buy dishes that have been boiled/fried, and not salads or desserts with cream
• wash your hands after using the toilet and before eating
• do not swim in open bodies of water where sewerage may enter

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Typhoid fever is considered an infectious disease from the category of anthroponoses with a characteristic fecal-oral route of infection. Although in our time the number of typhoid fever diseases in humans has significantly decreased, this problem has not yet been completely solved.

People in countries with unfavorable environmental conditions get sick especially often. In any case, the symptoms and treatment of typhoid fever are considered the prerogative of the doctor, since the pathology has a very complex course.

Typhoid fever - what is it?

Typhoid fever is an acute intestinal infection that has a cyclical course. As the pathology develops, damage to the intestinal lymphatic system, intoxication of the body and exanthema are observed.

Infection with typhoid fever occurs through nutrition. The incubation period lasts approximately 2 weeks. As the disease progresses, skin rashes, intoxication syndrome, and fever appear. In special situations, people experience hallucinations and inhibited reactions.

Pathogen and routes of transmission

The development of typhoid fever is a consequence of infection with the bacterium Salmonella enterica. It is a mobile gram-positive rod with a large number of flagella. This microorganism remains viable in the environment for several months and tolerates freezing well, but dies as a result of the action of chemical disinfectants and boiling.

The source of infection with typhoid fever is a sick person. Towards the end of the incubation period of typhoid fever, the pathogen begins to be released into the environment, and this continues throughout the entire period of the disease. Sometimes the process is observed even after the symptoms have disappeared. With the development of chronic carriage, the patient becomes a source of bacteria for life.

Pathogenic microorganisms are excreted in feces and urine, and they usually enter the body with water or food. Infection occurs when drinking water contaminated with feces or unheated food.

• Bacteria are often carried by flies. That is why the peak incidence is observed in summer and autumn.

The incubation period lasts on average 10-14 days, but sometimes this period is 3-25 days. As a rule, the pathology develops gradually, but sometimes an acute course is possible. With the gradual progression of the disease, a slow increase in temperature is observed and the indicator reaches high values ​​​​at about 4-6 days.

• Symptoms of intoxication of the body occur - weakness, insomnia, loss of appetite, headache, muscle discomfort.

The febrile period lasts about 2-3 weeks, and significant temperature changes are often observed during the day. One of the first symptoms of typhoid fever in humans is dryness and paleness of the skin.

The rash occurs approximately on the 8th-9th day of the disease - small red spots appear on the skin, not exceeding 3 mm in diameter, and when pressed they turn pale for a while. The rash is present for 3-5 days. If the disease has a complex course, the spots become hemorrhagic in nature.

During a physical examination, the doctor visualizes thickening of the tongue and the appearance of a white coating on it. Palpation of the abdomen allows one to identify bloating resulting from intestinal paresis. On days 5-7 of the disease, the size of the spleen and liver sometimes increases.

At the beginning of the development of the disease, a cough often occurs. At the peak of the disease, relative bradycardia appears, accompanied by severe fever. In this case, the pulse rate does not correspond to body temperature. Heart sounds become muffled, blood pressure decreases.

At the height of the disease, there is a pronounced progression of symptoms and severe intoxication. Toxic damage to the nervous system manifests itself in the form of hallucinations and inhibition of reactions.

As the temperature drops, the patient's condition improves noticeably. In some cases, after regression of symptoms, fever and intoxication develop, and exanthema appears. In this case, the typhoid infection worsens.

Test for typhoid fever

It is not possible to diagnose typhoid fever during the incubation period. At the initial stage of disease development, the following activities are carried out:

1. Serological analysis - in this case, the patient's serum is used to conduct an agglutination reaction.
2. Bacteriological method - consists of performing urine, feces and blood tests. Thanks to their implementation, it is possible to draw appropriate conclusions.

A timely examination for typhoid fever allows you to choose effective treatment and cope with this pathology.

Treatment of typhoid fever, drugs and diet

Treatment of typhoid fever is carried out in a hospital setting; the patient must remain in bed until the temperature drops. Usually, from the 8th day after a decrease in this indicator, it is allowed to sit, and on the 11th day - to move around.

The patient is partially transferred to parenteral nutrition. This avoids perforation of the intestinal walls. Food should be as gentle as possible from a mechanical and chemical point of view, but rather high-calorie foods are recommended.

It is imperative to exclude foods that provoke increased intestinal motility. These include black bread, beans, and cabbage. The basis of the diet is eggs, boiled meat, and fermented milk products. It is also useful to eat fruits and vegetables, but it is better to eat them in chopped form.

Etiotropic treatment is aimed at combating the causative agent of typhoid fever. Antibacterial drugs are used to help cope with the bacterium Salmonella enterica - chloramphenicol, ampicillin, amoxicillin, etc.

The use of immunomodulatory agents is of no small importance. Such drugs speed up the therapy process, making it more effective.

• For general strengthening of the body, probiotics, prebiotics and symbiotics are used. Doctors often prescribe a complex immunoglobulin preparation and vitamins.

Prevention

To prevent the development of typhoid fever, it is recommended to take the following precautions:

1. Adhere to hygiene rules, carefully process food, control the quality of drinking water.
2. Monitor the condition of people who have had symptoms of the disease.
3. After contact with the patient, it is important to monitor your condition for at least 21 days.
4. Disinfect areas where pathogenic microorganisms spread.

Vaccination against typhoid fever allows you to protect yourself from this dangerous disease. To carry out vaccination, a special sorbed anti-typhoid injection is performed.

Typhoid fever is considered a very serious disease that can cause death. To prevent this, it is very important to prevent the disease. If symptoms do appear, you should immediately consult a doctor for a detailed examination.

Typhoid fever develops when the Salmonella bacteria enters the body. It can be introduced into the intestines through unwashed food, contaminated water, and neglect of hygiene rules (for example, by simultaneously using towels with a person who is a carrier of the bacteria).

The route of transmission of infection is fecal-oral. Since the clinical picture of the disease does not have specific symptoms, to confirm the diagnosis it is necessary to conduct an analysis for typhoid fever, which will help determine the presence of the pathogen in the body.

When to test for typhoid fever

A blood test for typhoid fever can be taken in two cases:

• when a clinical manifestation characteristic of an intestinal infection appears;
• to prevent epidemics (is a mandatory analysis when renewing a health certificate).

If a patient goes to the doctor with a complaint about digestive problems and hyperthermia, the doctor, based on the manifestations of the disease, will make an assumption about the development of an intestinal infection. The presence of typhoid fever is indicated by the following patient complaints:

• abdominal pain;
• signs of poisoning (nausea, vomiting, weakness, loss of appetite, hyperthermia);
• problems with stool (constipation, somewhat less commonly diarrhea);
• dehydration (extreme thirst, tongue covered with a white coating, peeling skin);
• formation of roseola is possible (a skin rash appears a week after infection. When you press it, it disappears and then appears again. The number of rashes is from 4 to 25 elements).

Typhoid fever usually occurs as follows. Acute onset of the disease in 30% of cases. Symptoms of poisoning, deterioration of sleep, headache, weakness increase gradually. Body temperature increases over several days and reaches febrile values. Reaction inhibition appears, the stomach is swollen, flatulence and rumbling appear.

After a person has had typhoid fever, he develops a strong immunity to the typhoid bacillus.

The causative agent of typhus in fresh water can remain viable for up to a month, and in agricultural products for up to 10 days; in dairy products it multiplies and accumulates. Houseflies can also transfer the bacteria to food.

The first signs of the disease appear 7–23 days after infection, so it is extremely difficult to determine the exact source. Typhoid fever must be differentiated from tuberculosis, brucellosis, typhus, cholera, plague and other diseases in which the patient experiences fever and intoxication.

What tests are performed

To confirm typhoid fever, laboratory tests are prescribed, which must be carried out before starting antibiotic therapy (taking antibacterial drugs may affect the accuracy of the diagnosis).

For examination, blood, feces, urine, bile, and cerebrospinal fluid can be taken (if a complication is suspected). Depending on the stage of the disease and symptoms, the following tests for typhoid fever may be prescribed.

Serological study

It examines blood plasma. Necessary for the detection of specific antibodies produced by the human immune system. The analysis can be carried out only 4–5 days after infection with typhoid fever, since the body does not synthesize antibodies earlier.

General blood analysis

It is prescribed to determine the quantitative characteristics of all blood cells. When infected with typhoid fever, normal blood counts change.

Leukopenia occurs (the number of leukocytes decreases), aneosinophilia (eosinophils are absent), and the number of lymphocytes increases, which indicates the presence of infection in the blood.

Also, during typhoid fever, the level of neutrophils, leukocytes synthesized by the body during inflammation, increases, and the number of platelets, which are responsible for blood clotting, decreases.

A detailed blood test is required upon admission to hospital treatment and during therapy in order to monitor the dynamics. For the study, a blood test is taken from a vein or finger.

Blood biochemistry

Detects acute phase proteins and should be carried out before taking an antibiotic. The test requires 5–10 ml of blood from a vein, the results of the study can be found out within 24 hours.

Bacterial culture

There are few bacteria in the blood sample taken, so it is transferred to a nutrient medium (meat peptone broth) and placed in a thermostatic apparatus. Under favorable conditions, the microorganism will begin to form a large colony, which will be suitable for research.

Afterwards, chemical reagents are used and the type of bacteria is determined. A similar test is performed on all patients with hyperthermia, as well as when checking for typhoid fever. Results can be obtained 4-5 days after the analysis, a preliminary answer will be given after 2 days. Tank culture is the most accurate laboratory diagnosis of typhoid fever.

To detect antibodies to typhoid fever, a radioimmune or enzyme immunoassay method is used

RNGA and RPGA

To detect a person who is a carrier of the typhoid bacillus, as well as to monitor the effect of vaccination against typhoid fever, IRHA (indirect hemagglutination reaction) or passive hemagglutination (RPHA) is used. This method helps detect antigens and antibodies using red blood cells that precipitate when they come into contact with the antigen.

Red blood cells on which antigens are adsorbed stick together upon contact with the antibody. An immunological study determines the level of these antibodies. In a person suffering from typhoid fever, it can be at a level of 1:40, and in someone who has defeated the infection it is 1:2000, so diagnostics are carried out at intervals of 5 days to monitor the dynamics.

Bacteriological examination of stool

This test is rarely prescribed, since the typhoid bacillus leaves the body only 8–10 days after infection. This method is used to identify people who are carriers of the infection, but are not sick themselves.

Analysis of urine

Typhoid bacteria are detected in urine only 1–1.5 weeks after infection. A urine test can indicate such indirect evidence of typhoid fever as leukocytosis (at the initial stage of the disease, the number of white blood cells increases, and within 7 days it drops sharply), leukopenia, increased ESR, aneosinophilia, relative lymphocytosis.

Before collecting urine, the patient must perform hygiene of the external genitalia, then collect the material for analysis in a sterile jar. For diagnosis, 40–50 ml of urine will be sufficient. To test for infection, a sediment is used, which is transferred to a solid nutrient medium.

The ability to detect the causative agent of typhoid fever by microbiological methods is directly related to the number of bacteria in biological fluid and the use of antibacterial therapy. A week after infection with Salmonella S. Typhi, serological agglutination tests (RPGA for typhoid fever) give a positive response.

Serological tests are less specific than bacteriological methods, since a positive response may indicate a past infection caused by another species of Salmonella. An additional study after five days helps to monitor the increase in titer, which is characteristic of an acute infection.

Bacteria in the blood are found only in sick people; in the urine and feces, the bacteria can be found in both the sick person and the bacteria carrier

Do you need to prepare for the test?

A blood test for typhoid fever should be taken not only by patients with characteristic signs of the disease, but also by those who come into contact with a large number of people or food products when working. This is done to prevent the spread of typhoid fever, since an infected person can be a carrier of infection for a long time.

The patient excretes the greatest number of bacteria in feces during the period from the first to the fifth week of the disease, and in urine for 2–4 weeks. Every tenth person who has had an infection releases the typhoid bacillus into the external environment for 3 months, and 3–5% of the total number of typhoid patients are chronic carriers of the infection, spreading the bacillus for several years.

When passing and renewing a health certificate, a test for typhoid fever is mandatory. Many people do not know where the blood is taken for testing. To carry out diagnostics, venous blood is taken from the patient from the area of ​​the elbow.

The study is carried out in vitro, which literally means “in vitro”. How long the test takes depends on the workload of the laboratory; at a minimum, the result will be ready in two days. The doctor issuing the referral will clarify how to properly take a test for typhoid fever.

If there are no clarifications, then the following recommendations should be followed:

• You need to donate blood on an empty stomach;
• the day before the event, you should not eat too spicy, salty, fatty or smoked foods;
• it is necessary to exclude the intake of weak and strong alcoholic drinks, medications at least three days before donating blood;
• There is no need to change your drinking regime, but it is still better to give up coffee;
• Smoking is not allowed an hour before the test.

To avoid false-positive or false-negative tests, you need to take a responsible approach to donating blood.

If antibodies to typhoid fever are not detected, then this is confirmation that the person is not a carrier of the infection. If symptoms of the disease are present, and the test does not show the presence of a specific protein, then it is possible that the immune response has not yet been formed, since the pathology is at an early stage.

A positive result indicates that the patient has typhoid fever or is a bacteria carrier.

A false positive test result is possible if a bacteria from the genus Salmonella is present in the body, but causes another disease, that is, the microorganism is present and the immune system reacts by producing antibodies. The doctor will indicate what tests to take if you suspect typhoid fever or when checking for bacteria carriers, as well as where it is best to donate biological material.

If typhoid fever occurs in an acute form, the patient will be hospitalized in an infectious diseases hospital. The patient is prescribed antibiotics, diet and bed rest. It is recommended to avoid any overexertion, even when visiting the restroom. Typhoid fever, in the absence of adequate treatment, can lead to toxic shock and perforation of the intestinal mucosa. Therapy lasts from 2 to 4 weeks.

A test for typhoid fever is prescribed to patients to make an accurate diagnosis, since the disease has similar clinical manifestations to tuberculosis and brucellosis. All these diseases are united by severe intoxication of the body.

Typhoid fever is a disease caused by salmonella. It manifests itself as acute poisoning of the body, elevated body temperature, and a rash on the skin. The analysis will help to accurately establish the diagnosis and begin intensive therapy.

• elevated temperature accompanying fever;
• signs of acute poisoning of the body;
• cramps in the abdominal area;
• vomit;
• problems with bowel movements, or prolonged diarrhea;
• dehydration;
• weakness.

If such symptoms appear, the patient is immediately sent to donate blood for typhoid fever to confirm or refute the specialist’s suspicions. A doctor can make an accurate diagnosis only after collecting an anamnesis, performing an external examination, and receiving data from clinical studies.

People of certain professions are required to take such an analysis. Doctors, people working in children's groups and the food industry are at risk. Similar tests are taken from representatives of the food trade. For those who are at risk, a special medical examination is carried out once a year to exclude and prevent the spread of typhoid fever. All data obtained during the survey is recorded in the employees’ health records.

At the slightest suspicion of the development of typhoid fever, the patient is sent for tests so that the doctor can confirm or refute the alleged diagnosis. Since the disease has a number of similar clinical manifestations with other infections, only a comprehensive examination gives an accurate picture of a person’s health status.

A blood test for typhoid fever requires certain preparation, which is necessary to make a correct diagnosis. Three days before donating blood, taking any medications is prohibited. You should give up alcohol and alcohol-containing tinctures 48 hours before.

On the day of the study, exclude from food consumption:

• eggs,
• dairy products,
• smoked products,
• spicy and fatty foods.

One hour before blood sampling, it is recommended to refrain from smoking and drinking caffeine-containing drinks. If you do not follow the preparation recommendations before taking blood, this may lead to changes in the result of the analysis. As a result, a specialist may make an incorrect diagnosis and prescribe the wrong treatment, which will lead to a deterioration in health. If you do not follow the preparation recommendations, you should inform your doctor and undergo the test again.

Before undergoing laboratory tests, careful preparation is required, which should begin at least 3 days before the scheduled date. This will help avoid false positive or false negative results.

You should ask your doctor about the rules of preparatory measures.

An analysis for typhoid fever is carried out for diagnostic purposes according to the following indicators:

1. A general blood test performed for any infectious diseases. Studies show indirect signs of typhoid fever, manifested in changes in leukocyte counts, increased ESR, and the absence of eosinophils.
2. Bacterial cultures should be taken to establish the growth of microflora and its classification.
3. Biochemical analysis establishes the presence of proteins indicating the development of the disease.
4. On the fourth day from the onset of the disease, an antibody test is taken.
5. Immunoenzyme tests.
6. Reaction of mediated hemagglutination.

If there are positive results, we can say that the disease is either actively developing in the human body, or it was previously transferred, and the body has developed antibodies, which give a positive result.

Typhoid fever, the test for which is positive, may be in an acute or inactive form.

You can talk about a specific diagnosis only after the research results on all of the above points are ready. Separately, each analysis taken can only indirectly indicate the manifestation of the disease.