Residual nitrogen in the blood, analysis, normal. What are blood biochemistry and residual nitrogen?
What are residual nitrogen, blood biochemistry and interpretation of test results? These questions interest many patients. Blood biochemistry has great importance in the diagnosis of diseases and is widely used modern doctors. Using this analysis, many serious illnesses eg diabetes, different kinds anemia, cancer. Residual nitrogen is the total amount of nitrogen-containing substances in the blood after protein compounds are removed from it. Most nitrogen is found in proteins. Residual nitrogen is present in urea, amino acids, creatine, ammonia, and indican.
What is a biochemical blood test?
Blood biochemistry is an indicative analysis that allows high probability identify changes in tissues and organs in the early stages. Preparation for donating blood for biochemistry is carried out in the same way as before a regular test. Blood for research is taken from the ulnar vein.
Important criteria are:
- presence of protein;
- level fat metabolism;
- bilirubin content;
- nitrogen fractions, for example, residual nitrogen, urea, creatinine and inorganic compounds.
Protein and its components in blood plasma
One of the main components in blood plasma is protein and its fractions.
The protein content in blood plasma is 65-85 g/l. This is approximately 2-4 g/l more than in whey. If there are more proteins, then this condition is called hyperproteinemia, if less - hypoproteinemia.
These diseases are a consequence of:
- renal dysfunction;
- poor diet, prolonged fasting, low protein diet;
- gastrointestinal diseases;
- blood loss;
- oncological diseases;
- liver diseases.
If there are too many proteins, it may be caused by:
- overheating of the body;
- serious burns with a large area affected;
- injuries;
- myeloma;
- cholera.
Based on their composition, proteins are divided into several types: albumins, globulins, fibrinogens. Albumin is the most abundant. It is difficult to overestimate their importance: they help retain water in the body and maintain normal blood pressure.
If the level is elevated, this is often the cause of edema. An increased amount of albumin is very often a consequence of an improper diet, loss or breakdown of proteins, and dehydration of the body.
There are several types of globulins. If their number is not normal, this may be caused by:
- inflammation in the body;
- state of stress due to traumatic injuries;
- infectious diseases;
- diseases of a rheumatic nature;
- chronic diseases of various etiologies;
- oncological diseases.
Depending on which proteins are more and which are less, the doctor draws conclusions about how intense the disease is. For example, reduced level alpha globulins indicate dysfunction of the liver and thyroid function.
Deviations from the norm in globulin levels are often associated with the occurrence of diabetes mellitus, vascular diseases, kidney diseases. An increase in the amount of globulins in plasma is also associated with dysfunction immune system, for example, with infectious, helminthic, purulent diseases: pathologies cartilage tissue, oncological diseases blood, tumors.
An increase in alpha globulin occurs with hepatitis and liver dysfunction. An indicative sign of acute diseases such as AIDS, wasting, allergic reactions, is a decrease in alpha globulin levels.
What does fat metabolism indicate?
When talking about fat metabolism in the body, the doctor first of all pays attention to lipid levels. It is an important diagnostic indicator that will help determine pathologies of fat metabolism. Lipids themselves are low molecular weight substances that are insoluble in water, but are perfectly soluble in essential and organic compounds.
Lipids are present in blood plasma, but in the form of lipoproteins, which are divided into several types:
- cholesterol;
- triglycerides;
- phospholipids.
When researching in the laboratory great attention focuses specifically on cholesterol. To identify the overall picture, all lipoproteins are assessed.
Cholesterol is a type of alcohol that is found in cell membranes. The normal level is considered to be from 3.9 to 6.5 mmol/l. For women this figure is lower. Cholesterol levels are unstable and vary with age. physical condition person, time of year.
An increase in cholesterol may indicate atherosclerosis or possible risk the appearance of this disease. Besides, high cholesterol is a harbinger coronary disease heart, vascular diseases. However, even with normal level cholesterol, there is a possibility of these diseases occurring.
Low cholesterol often occurs due to:
- diabetes mellitus;
- thyroid diseases;
- kidney pathologies with the development of edema;
- liver diseases;
- pregnancy;
- tuberculosis;
- pancreatitis and pancreatic dysfunction.
To determine the level of fat metabolism, blood is taken on an empty stomach; at least 12-14 hours must pass after the last meal. If you break this rule, the test result may be inaccurate.
Bilirubin occurs in the body due to... They are responsible for its production Bone marrow, liver and spleen. Normal content bilirubin does not exceed 8.5-20.5 µmol/l. With an increase in the amount of bilirubin skin covering and the mucous membranes become yellow.
There are two types of bilirubin: direct and indirect. The study is carried out using a diazo reagent, which gives a certain reaction with a given compound.
Bilirubin formation occurs in the liver. It has the ability to penetrate the gallbladder. Blood often contains increased amount this component.
This may be due to:
- intense;
- various lesions of liver tissue;
- stagnation in gallbladder and liver.
Often, increased breakdown of red blood cells is associated with serious diseases, for example, anemia, malaria. In addition, it can be observed during heart attacks, with extensive hemorrhages, liver damage, oncological diseases. The outflow of bile may be associated with the formation of stones or tumors.
What is residual nitrogen?
Residual nitrogen is formed after blood is purified from proteins. The norm is 14.3 mmol/l -28.6 mmol/l. When kidney function is impaired, the amount of residual nitrogen in the blood increases.
A similar condition develops against the background of:
- chronic kidney disease;
- polycystic disease;
- hydronephrosis;
- tuberculous kidney damage;
- stones in the ureters.
Thus, a blood biochemistry test is the most important indicator, on the basis of which conclusions can be drawn about the patient’s health status.
Nitrogen is part of many complex molecules and is therefore present in all living tissues. Residual blood nitrogen (RBN) is the nitrogen determined in the serum after the precipitation of all proteins contained in the blood. It is part of non-protein compounds, in particular urea, creatinine, amino acids, etc.
The total indicator of residual nitrogen has significant diagnostic interest and is used to identify or confirm large quantity pathological conditions.
When is the study ordered?
Determination of the AO level is prescribed in two cases:
- if there is a suspicion of the development of hepatic or renal failure;
- as a preventative study.
Preparing for the test
To avoid errors in the blood test for residual nitrogen, it is necessary to properly prepare for the visit to the laboratory. Since the test for OA is part of the biochemical analysis, preparation is carried out according to the general rules:
- It is recommended to donate blood in the same laboratory. Especially if the analysis showed a deviation from the norm.
- To determine the level of OA is used deoxygenated blood. But in some cases, the fence can be done using a finger.
- The collection of material for research should be carried out strictly on an empty stomach. The “hungry” period should be eight to twelve hours. On the morning of the laboratory visit, you are allowed to drink only clean water no gases.
- The material is collected between 7 and 11 hours.
- Before visiting the laboratory office, you must eat as usual for three days, but exclude/limit fatty, fried and spicy dishes/foods.
- Sports and any active activities physical exercise should be excluded because they are capable of changing high-quality composition blood.
- It is advisable to refuse admission medicines, if possible. IN otherwise Tell your doctor about your treatment.
- Before donating blood, you need to sit in the waiting room and calm down.
Proper preparation allows you to obtain the most reliable results.
Decoding the results obtained
The range of residual blood nitrogen allowed by doctors is 14.3 – 26.8 mmol/l. At the same time, doctors allow a short-term increase in OA up to 35 mmol/l, but provided there are no other pathological symptoms. The reason for the increase may be natural causes, in particular:
- content in the menu of a significant amount of nitrogen-containing food;
- dry food;
- the increase occurs before the onset of labor;
- significant physical activity, etc.
But a significant increase in the level of residual nitrogen is a sign of existing pathology. A decrease in this indicator is also a bad prognostic symptom.
Increase in residual blood nitrogen
The condition in which an increase in the level of OA is determined is called azotemia. There are two types of it:
- retention. Pathological condition, characterized by abnormalities in the excretory function of the kidneys. The patient is diagnosed with renal failure;
- production. Fixed as a result of accelerated destruction of protein tissues. In most cases, kidney function is not affected.
The reasons for the development of retention azotemia are:
- pyelonephritis;
- polycystic disease;
- glomerulonephritis;
- kidney tuberculosis;
- kidney hydronephrosis;
- nephropathy that developed during pregnancy;
- arterial hypertension accompanied by renal pathology;
- blockage of the ureter - the presence of sand, stones, neoplasms of various types.
Productive azotemia is provoked by:
- severe fevers;
- disintegration of neoplasms of any type.
Diagnosis mixed type Azotemia is a rare result, but still occurs. The cause of the pathology in this case becomes:
- ingestion of highly toxic components, in particular mercury salts, into the body;
- injury caused by prolonged compression or crushing of living tissue.
In such cases, combined (mixed) azotemia is diagnosed, accompanied by necrotization of the renal tissue.
Important! Increase in OA index over 20 times (relative to permissible norm) is called hyperazotemia. The condition is a consequence of the development of mixed azotemia. But it can also form as a result of severe kidney damage.
An increase in OA can develop not only as a result of damage to the renal system. The reasons may be:
- pathologies of the adrenal glands, accompanied by dysfunction;
- heart failure;
- burns of a large surface of the skin;
- state of dehydration;
- infections of bacterial origin;
- stomach bleeding;
- stressful conditions.
Reduced residual nitrogen levels
A decrease in OA levels is also a sign of some pathology. The following diseases may be the causes:
- liver problems accompanied by insufficient production of urea;
- intestinal disorder;
- uncontrollable vomiting;
- intensification of protein production;
- following a low protein diet.
Treatment of the condition consists of eliminating the root causes that caused it. If a deviation is detected, the patient is prescribed a series of additional tests to help clarify the diagnosis. Therapy is prescribed after receiving all research results.
When diagnosing most diseases, patients are prescribed biochemical research blood, which can be used to determine condition of all body systems. Among the many indicators obtained in this study, the content of residual nitrogen in the blood plays an important role.
IN human body nitrogen plays an important role, it exists in the form of various compounds. The important element nitric oxide is fundamentally different from residual nitrogen.
Nitric oxide is responsible for the functioning of the heart and is involved in the creation of new blood vessels, determines their tone and patency. NO is needed for proper development all muscles, helps to dilate blood vessels, prevent spasms, and relieve pain. A nitric oxide level of up to 2.4 g/ml is considered normal. To saturate the body with this element, it is used biologically active additives, as well as special diets.
Residual nitrogen content in the blood
Residual nitrogen means nitrogen containing elements, remaining in the blood after filtering out proteins. Using value total indicator and individual indicators can be diagnosed possible pathologies. Residual nitrogen consists of 15 compounds representing metabolic products of proteins and nucleic acids, the following indicators are especially important:
- Urea is about 50%;
- Amino acids 25%;
- Ergotin 8%;
- Uric acid 4%;
- Creatine 5%;
- Creatinine 2.5%;
- Ammonia and indican 0.5%;
- Polypeptides, nucleotides and nitrogenous bases 5%.
Watch the video about creatinine
Biochemical analysis residual nitrogen must be tested if kidney disease is suspected, it also carries important information for tumor formations.
Increased levels of residual nitrogen in the blood occur with azotemia, but are no less dangerous reduced values, This possible sign hypoazotemia.
Ask your question to a clinical laboratory diagnostics doctor
Anna Poniaeva. Graduated from Nizhny Novgorod medical academy(2007-2014) and Residency in Clinical Laboratory Diagnostics (2014-2016).
Low molecular weight nitrogenous substances are represented mainly by metabolic products of proteins and nucleic acids. These substances remain in the supernatant or filtrate after precipitation of large molecular proteins and constitute residual blood nitrogen. The main fractions of residual nitrogen are urea(approximately 50%), amino acids(about 25%), creatine And creatinine(7,5%), polypeptides, nucleotides And nitrogenous bases (5%), uric acid (4%), ammonia And indican(0,5%).
An increase in residual nitrogen fractions (azotemia) in nature can be absolute, associated with the actual accumulation of nitrogenous components in the blood, and relative, associated with dehydration. In turn, absolute azotemia can be retentional (renal origin) and production. Retention occurs as a result of delayed excretion and differs in azotemia of renal origin (glomerular diseases - nephritis, renal tuberculosis, nephrosclerosis, etc.) and extrarenal origin. Extrarenal, in turn, are divided into adrenal (the result of hemodynamic disorders and a drop in filtration pressure during cardiovascular failure, decreased blood pressure) and subrenal (with hypertrophy or prostate adenoma, kidney stone disease). Production azotemia is detected in all conditions associated with increased protein breakdown; it is distinguished from retention by an increase in the content of amino acids in the blood, as well as the simultaneous accumulation of nitrogenous components in the blood and urine.
Some laboratories still use the determination of total residual nitrogen, but most diagnostic value has a determination of the concentration of its individual components.
Urea (MW 60 D) is synthesized in hepatocytes from ammonia and carbamoyl phosphate in the ornithine cycle, spreads throughout the body in the blood, easily penetrates cell membranes and is evenly distributed in the extracellular and intracellular spaces. In the kidneys, urea is completely filtered, 40-50% of it is reabsorbed in the renal tubules and actively secreted by tubular cells. Urea nitrogen makes up about 90% of the total nitrogen excreted. When 80-100 g of protein is consumed with food, 25-30 g of urea per day is formed and excreted in the urine.
Creatine is synthesized from glycine, arginine and methionine through sequential reactions in the kidneys and liver. From here, creatine is delivered through the bloodstream to the muscles and is phosphorylated to form creatine phosphate. Further, during spontaneous hydrolysis (1-2%) or after the transfer of the phosphorus group from creatine phosphate to adenylic acid, creatinine is formed from creatine, which is excreted in the urine. Normally, the amount of creatinine in urine corresponds to muscle mass body and does not depend on the daily amount of urine. IN clinical practice determine the content of creatine and creatinine in blood serum and urine.
Polypeptides enter the blood partly from the intestines (during the digestion of proteins), partly from tissues as a result of the breakdown of tissue proteins.
Uric acid (MW 168 kDa) is formed mainly in the liver during the breakdown of purine nucleotides (adenine and guanine) supplied with food, endogenous and synthesized de novo. About 80-85% of it is excreted by the kidneys, the rest through the intestines. Renal excretion uric acid depends on the filtered amount, which is almost completely reabsorbed in the proximal tubule, as well as secretion and reabsorption in the distal tubule, resulting in about 10% of the filtered uric acid being excreted. In blood plasma, uric acid is found in the form of sodium urate in a concentration close to saturation. Therefore, if there is excess in the blood normal values there is a possibility of crystallization of urates.
Indican is a potassium or sodium salt indoxylsulfuric acid, formed in the liver during the neutralization of indole. Indole appears in the intestines during the decay of proteins from the amino acid tryptophan. In addition to indoxyl sulfuric acid, indoxylglucuronic acid is also formed in the liver. Both indole derivatives are water soluble and are excreted in the urine.nitrogen of non-protein compounds (urea, amino acids, uric acid, creatine and creatinine, ammonia, indican, etc.) remaining in the blood serum after protein precipitation is completed. Concentration of A. o. in blood serum is a useful diagnostic indicator for many diseases.
Normal concentration of A. o. in blood serum is 14.3-28.6 mmol/l. or 20-40 mg /100 ml. and the content in the daily amount of urine forms 714-1071 mmol. or 10-15 G. From time to time, the percentage ratio of urea nitrogen to amino acid is determined. (normal is about 48%). With renal failure, this coefficient increases and can be about 90%, and if the urea-forming function of the liver is impaired, it decreases significantly (below 45%).
Increasing the content of A. o. in the blood (azotemia) is observed in renal failure (due to impaired excretory function of the kidneys), and in heart failure, malignant tumors, infectious diseases(due to increased breakdown of tissue proteins and increased content of non-protein nitrogen-containing compounds in the blood). Decrease in concentration of A. o. observed during pregnancy (first two trimesters), with severe liver failure.
A. o. determined in a protein-free filtrate or supernatant after removal of precipitated serum proteins by centrifugation using the azotometric Kjeldahl method and its many modifications, and colorimetric and hypobromite methods. The Kjeldahl method consists of the precipitation of proteins with trichloroacetic acid, the mineralization of the supernatant in the presence of concentrated sulfuric acid, the distillation of the resulting ammonia and its quantification. In the practice of clinical diagnostic laboratories, the Kjeldahl method is rarely used, mostly to check the accuracy of other methods for determining nitrogen. For serial studies, the Kjeldahl method is of little use due to its labor intensity. In the USSR, unified methods for determining A. o. in blood serum are the colorimetric method with Nessler's reagent (after combustion of the protein-free filtrate with sulfuric acid, nitrogen-containing compounds transform into ammonium sulfate, which with Nessler's reagent gives a yellow color; the color intensity of the test solution is compared with the color intensity of a control solution with a known nitrogen content) and hypobromite method (when acting on protein-free filtrate alkaline solution hypobromite, nitrogen is released in the form of gas, the remainder of unreacted hypobromite is determined by iodometric titration; the amount of hypobromite sent to the reaction corresponds to the amount of A. o. in the sample).
In the air of the room in which the determination of A. o. there should be no ammonia impurities. Therefore, urine tests and reagents containing ammonia cannot be stored in this room.
Bibliography: Laboratory methods of studying in the clinic, ed. V.V. Menshikova, s. 215, M. 1987.
1. Small medical encyclopedia. - M. Medical encyclopedia. 1991-96 2. First aid. - M. Gromadnaya Russian Encyclopedia. 1994 3. encyclopedic Dictionary medical terms. - M. Soviet Encyclopedia. - 1982-1984
See what “residual nitrogen” is in other dictionaries:
residual nitrogen- (syn. A. protein-free, A. non-protein) A. part of the non-protein nitrogenous substances of blood, muscles and other tissues; change in the content of A. o. in the blood serum indicates a violation of nitrogen metabolism in the body ... Big Medical Dictionary
Nitrogen- I Nitrogen (Nitrogenium, N) chemical element of group V of the periodic system D.I. Mendeleev, one of the most common in nature chemical elements. In all living organisms, A. is represented by proteins (Proteins), amino acids ... Medical encyclopedia
protein-free nitrogen
non-protein nitrogen- see residual nitrogen ... Big medical dictionary
Nitrogen metabolism- totality chemical transformations, reactions of synthesis and breakdown of nitrogenous compounds in the body; component metabolism and energy. The concept of nitrogen metabolism includes protein metabolism(a set of chemical transformations in the body ... Medical encyclopedia
Urea- I Urea (synonym urea) is an amide of carbonic acid, the end product of protein metabolism in so-called ureotelic animals and humans. When consuming 100-120 g of protein in the urine per day with a daily diet, 20-25 g of urea are excreted per day... Medical encyclopedia
Amino acids- I Amino acids (synonym for aminocarboxylic acids) organic compounds, whose molecules contain amino groups (NH2 groups) and carboxyl groups (COOH groups); are the elements from which peptides and proteins are built. About 200 are known ... Medical encyclopedia
BLOOD- BLOOD, a liquid that fills the arteries, veins and capillaries of the body and is composed of a transparent, pale yellowish color. the colors of the plaza we are and suspended in it shaped elements: red blood cells, or red blood cells, white cells, or leukocytes, and blood plaques, or ... A huge medical encyclopedia
Breath- in the commonly used sense, denotes a series of movements continuously alternating throughout life chest in the form of inhalation and exhalation and determining, on the one hand, an influx of fresh air into the lungs, and on the other, the removal of already broken air from them... Encyclopedic Dictionary of F.A. Brockhaus and I.A. Efron
Blood chemistry- Biochemical blood test is a laboratory method of study used in medicine, which reflects the functional state of organs and systems of the human body. It allows you to find out the function of the liver, kidneys, active inflammatory ... Wikipedia
KIDNEYS- KIDNEYS. Contents: I. Anatomy of P. $65 II. Histology P. 668 III. Comparative Physiology 11. 675 IV. Pat. Anatomy II. 680 V. Functional diagnostics 11. 6 89 VI. Clinic P ... Huge medical encyclopedia
Books
- Nutrition for kidney diseases. Absent. Medical nutrition plays a huge role in all kidney diseases. It is set depending on functional state kidneys, based on this in each special case the doctor must Read more Buy the e-book for 29.95 rubles
- Nutrition for kidney diseases. Ilya Melnikov. Therapeutic nutrition plays a huge role in all kidney diseases. It is established depending on the functional state of the kidneys, based on this, in each individual case the doctor must Read more Buy for an e-book
Loading...
