What is urea in the blood: the norm and deviations of indicators, the rules for the treatment of abnormal kidney function. How much urea in the blood should a woman normally have

What is urea?

Urea is one of the products of protein metabolism in the body. At normal operation excretory system, this substance is quickly excreted along with the urine. But if the urea in the blood is elevated, then this, as a rule, indicates serious problems in the work of the kidneys. As already mentioned, this substance is formed as a result of the breakdown of protein components. During the exchange of proteins, ammonia is formed, which is toxic to the body. Therefore, in the liver, this substance is converted and excreted from the body in the form of urea. Normally, the level of this metabolic product is 2.5-6.4 mmol / l in adults and 1.8-6.4 mmol / l in children. In case of any deviation from these indicators, it is necessary to carry out additional research to determine what the problem is. By the way, urea in the urine in this case is lowered, since it is not excreted by the kidneys, but accumulates in the blood.

Blood test for urea level

The analysis can give the doctor a lot useful information about the state of human health. Sampling in this case is carried out in the morning, since last appointment food should be no earlier than eight hours before the procedure. Laboratory research gives the doctor the opportunity to judge the condition and work of organs such as the kidneys and liver. In any case, if urea is elevated, it is worth going through full examination organism. Self-medication or complete ignoring of the problem is unlikely to help.

Why is urea in the blood elevated?

Slight fluctuations in the level of urea are quite acceptable, since they depend on the characteristics of human nutrition, as well as the activity of life. For example, an increase in performance is possible when eating a large amount of protein foods or after physical exertion. But in most cases, a similar symptom can signal a mass of different diseases:

Urea in the blood is increased: what to do?

Of course, first you need to go medical checkup, paying special attention to the study of the kidneys and liver. Sometimes blood tests for hormones are also required. Therapy in this case depends entirely on the disease that caused this symptom. For example, for problems with the endocrine system, hormonal drugs are indicated, and for inflammation of the kidneys, patients are prescribed anti-inflammatory, diuretic drugs, and antibiotics. In any case, as soon as it is eliminated primary cause, level uric acid will return to normal.

Urea in the blood is of great diagnostic value. A blood test for urea is a mandatory study for patients with kidney and liver dysfunctions. Since urea is a specific product of protein metabolism, this analysis allows you to assess the degree of intensity of protein breakdown in the body.

By a pronounced increase in the concentration of urea in the blood, it can be judged that a violation of kidney function has occurred (chronic or acute renal failure). Proteins are often fixed in the urine at the same time.

It is important that the increase in dysfunction entails a complex process of penetration of urea through the gastrointestinal mucosa with subsequent conversion to ammonia, which, through its effect on the mucosa, activates its toxic inflammation (gastritis, duodenitis, etc.)

For reference. AT sports medicine, a blood test for urea is widely used to monitor the rate of recovery of the body after intense physical exertion.

In the process of urea formation, toxic ammonia is actively detoxified in the liver.

Subsequently, urea from the liver cells is released into the systemic circulation and transported to the kidneys for further disposal in the urine. In this case, from forty to sixty percent of urea can be absorbed back into the blood.

The rate of reabsorption directly depends on the rate of tubular reabsorption in the kidneys and the level of ADH (antidiuretic hormone) in the body. Also, the volume of diuresis affects the level of urea. In patients with anuria (absence of urine) or oliguria (decreased amount of urine) against the background of acute kidney dysfunction or heart failure, exicosis, thirst, etc., the reabsorption of urea into the blood increases dramatically.

Due to this, elevated levels of urea in the blood plasma make it possible to suspect that the patient has significant deviations in the processes of glomerular filtration.

What is urea in urine and when is it examined

For reference. The level of urea in the urine is included in the list of basic studies conducted to monitor the excretory capacity of the kidneys. The urea index in blood plasma and urine, as well as their ratio, allows us to assess the degree of impaired renal function and to make a differential diagnosis between prerenal and postrenal azotemia.

Evaluation of the level of urea in the urine is usually carried out when it is detected. high level in the blood, to clarify the diagnosis and assess the excretory ability of the kidneys.

When is blood urea measured?

suspected liver and kidney disease;
assessment of the severity of acute and chronic insufficiency kidney function, as well as liver failure;
monitoring the effectiveness of the prescribed diet with the most limited amount of protein consumed (low protein diet) in patients with chronic renal failure;
violations of protein metabolism and any diseases accompanied by a violation of protein metabolism;
electrolyte imbalance;
dehydration;
anuria and oligonuria of any origin (acute renal failure, heart failure, shock, intoxication, sepsis, etc.;
carrying out differential diagnosis between prerenal and postrenal azotemias (in this case, the ratio of urea and creatinine is estimated);
assessment of kidney damage in arterial hypertension and hypertensive crisis, diabetes mellitus (diabetic nephropathy), atherosclerosis renal arteries(kidney ischemia);
monitoring the effectiveness of ongoing hemodialysis;
monitoring of kidney and liver function in the treatment of hepato- and nephrotoxic drugs;
carrying out intensive care;
pregnancy (blood urea is included in the list of standard studies);
malabsorption syndrome (syndrome of impaired absorption in the intestine);
abdominal trauma.

Urea to creatinine ratio

Attention. This coefficient (index) is determined in patients with azotemia, to clarify its type (prerenal, renal or postrenal). The index is calculated by the ratio of urea nitrogen to the level of creatinine. normal index nitrogen is considered equal to 15.

Prerenal azotemia is characterized by an increase in the index of more than 15. In this case, the glomerular filtration rate increases due to insufficient blood supply to the kidneys. As a result of this, the total nitrogen and creatinine levels rise sharply.

This condition develops against the background of a decrease in cardiac output and ischemia of the kidneys, as a result of their poor blood supply. Prerenal azotemias can develop in patients with heart failure, massive blood loss, or shock.

With the development of renal (renal) azotemia against the background of acute and chronic renal failure, glomerulonephritis, tubular necrosis, gout, diabetic nephropathy, etc., the index is below 15. At the same time, there is a decrease in the glomerular filtration rate and an increase in the level of creatinine with nitrogen urea in the blood.

Important. Urea in the blood is also increased in postrenal azotemia. In this case, the index exceeds 15. Postrenal azotemia can be observed in patients with vesicoureteral reflux, obstruction of the outflow of urine by a stone or tumor, prostatic hyperplasia, hydronephrosis.

How to determine the level of urea in the blood

Used to determine the level of urea in the blood venous blood(serum), which is examined using the kinetic (urease) UV method.

AT standard mode, the results of the analysis can be obtained the next day. If it is necessary to urgently determine the level of urea in the blood, the analysis is performed in two hours.

The results of the study are recorded in mol / liter.

It is advisable to donate blood in the morning, before meals. It is forbidden to drink alcohol, strong coffee, tea and sweet carbonated drinks.

What can affect the results of a blood urea test

nalidixic acid,
acyclovir,
allopurinol,
aminocaproic acid,
cefazolin,
cefixime,
cefoperazone,
cefotaxime,
cefotetan,
cefoxitin,
cefpodoxime,
ceftriaxone,
kanamycin,
levodopa,
lidocaine,
losartan, and a number of others, including vitamin D.

Attention! To obtain an adequate result, you should discuss with your doctor a temporary discontinuation of the drug. medicines. Just don't make your own decision!

Drugs can lead to a decrease in the level of urea in the blood ascorbic acid, phenothiazine, treatment with anabolic hormones.

Urea in the blood - the norm

The rate of urea in the blood may vary slightly in different laboratories. The norm for urea in the blood for patients older than fourteen and younger than sixty years is from 2.5 to 6.4 mmol per liter. Some laboratories may report values from 2.5 to 8.3.

The norm of urea in the blood in women is somewhat lower than in men. With age, upper bound the norm for urea increases. This is due to the age-related decrease in the filtration capacity of the kidneys. On average, urea values increase by 1 mmol per liter.

Urea norm in men in the blood can increase with active physical training. Such a picture is physiological if the increase is moderate and is not accompanied by a violation of the excretory function of the kidneys, a change in the level of creatinine, or other abnormalities in the analyzes.

Urea in the blood is the norm for women and men over sixty years old is from 2.9 to 7.5.

Attention. In children, urea in the blood largely depends on age. In the first few days after birth, the urea level in the baby corresponds to adult levels. In premature babies, blood urea is increased to 8.9 mmol per liter. The lower values are from 1.1.

Such azotemia, in this case, is physiological and is due to high catabolism, the lack of sufficient fluid intake into the child's body and a low level of filtration in the glomeruli. Physiologically increased urea for the first two or three days. Full normalization of values should occur by the end of the first week of the baby's life.

Further, blood urea in children is lower than in adults.

Urea in the blood is increased - causes

Such changes in the analyzes can be observed in patients with:

dehydration;
electrolyte imbalance;
violation of the utilization of protein decay products;
enhanced protein catabolism;
decreased excretory function of the kidneys (including age-related changes in patients old age and children of the first days of life);
glomerulonephritis
pyelonephritis;
renal amyloidosis;
kidney tuberculosis;
acute and chronic renal failure;
heart failure;
shocks, blood loss, poisoning and intoxication;
burns;
intestinal obstruction;
violation of the outflow of urine (stones in the ureters and bladder, tumors Bladder etc). Elevated urea in the blood in men can be observed with hyperplasia or prostate cancer);
malignant neoplasms;
leukemia;
ketoacidosis against the background of diabetes mellitus;
fevers;
exhaustion.

Attention. Also, increased urea in the blood can be observed with excessive physical exertion (more often in men) and excessive intake of products with high content proteins.

Urea in the blood is lowered - causes

severe liver diseases, accompanied by a violation of its function - cirrhosis, hepatitis, acute hepatodystrophy, hepatic coma, liver tumors, etc. (in this case, the synthesis of urea by the liver cells is directly disrupted);
phosphorus and arsenic poisoning;
hyperhydration (excessive fluid intake);
congenital diseases accompanied by a deficiency of enzymes necessary for the synthesis of urea;
acromegaly;
pathologically increased protein losses (syndromes of impaired absorption in the intestine: malabsorption, celiac disease, etc.);
impaired secretion of antidiuretic hormone;
hereditary hyperammonemia.

Attention. Also, a decrease in the level of urea in the blood is typical for vegetarians, patients on a low-protein diet or on hemodialysis.

A physiological decrease in urea is typical for pregnant women, especially in the third trimester, as well as children in the first week of life and up to 14 years of age.

What to do with an increased or decreased level of urea

Important! Violation of the utilization of protein breakdown products always indicates serious violations of the functions of the kidneys and liver. That's why self-treatment with help folk methods and diuretics are not allowed.

All drug therapy selected by the attending physician after a thorough examination.

It must be understood that with a decrease in kidney function, all treatment is carried out under close monitoring of laboratory parameters. At the same time, the amount of not only the protein level, but even the amount of liquid consumed by the patient is calculated very carefully.

Attention. Non-drug correction of urea parameters can be carried out only if its decrease or increase is due to incorrect physical activity or malnutrition.

Some patients pay special attention to a health problem when, according to the results of an analysis, urea in the blood is increased - reasons for how to treat an ailment with high rate efficiency is best discussed with your doctor. This is an important indicator of the specified biological fluid, which is a metabolite of protein metabolism and indicates an internal imbalance.

Urea in the blood - what is it

Before determining a specific disease, the doctor recommends undergoing diagnostics, which includes mandatory testing. Uric acid in the blood combines half of the sedimentary nitrogen in the body, and its main function is to neutralize ammonia. The concentration of urea is an unstable indicator, but depends on physiological features. The protein penetrates with food, breaks down to an amino acid, resulting in the formation of ammonia, which is toxic in effect. The liver produces urea, which is excreted from biological fluid from the body.

The rate of urea in the blood

Before choosing effective method how to reduce the level of uric acid in the blood with home methods, it is important to determine the acceptable limits of the norm, consult a doctor. In addition, it is required to identify the nature of the pathology, the degree of its neglect. The rate of uric acid in the blood is determined by the age of the patient, stipulates the following allowable limits:

for babies - 1.3-5.4 mol / l;
child 1-14 years of age - 1.7-6.6 mol / l;
pensioners from 60 years old - 2.7-7.6 mol / l.

Among women

The urea index has its differences by gender. If increased, it is possible serious illness organism. For example, the rate of urea in the blood in women is lower than in men due to the physiological characteristics of the body. Before looking for reasons, it is worth clarifying that for the fairer sex before the age of 60, the limit of the norm is the limit of 2.3-6.5 mmol / l.

In men

For representatives of the stronger sex, the allowable interval is increased, so it is not worth comparing with female indicators. The rate of urea in the blood in men ranges from 3.7-7.5 mmol / l. It is important to identify early main reason such a serious disorder, treat it medical methods. It's time to figure out what it can mean when uric acid in the blood is elevated.

Causes of increased urea in the blood

Outwardly, the pathology may not manifest itself in any way, and the patient only complains of weakness, general malaise, while not being able to understand his condition without medical care. The reasons for the increased content of urea in the blood can be physiological and pathogenic. In the first case, nothing serious, after a while you need to retake a blood test. In the second case - without elimination pathogenic factor there is no positive trend at all. So, due to physiological factors, elevated uric acid is provoked by the following anomalies:

nervous stress;
excessive physical activity;
severe fatigue and insomnia;
excess protein from the daily menu;
postoperative condition;
wrong daily diet;
progressive pregnancy;
long-term use individual medicines;
prolonged fasting, strict diet;
decrease in pressure against the background of weather changes.

Pathological causes why there is an increase in urea in the blood are detailed below:

typhoid fever;
rheumatic diseases;
arterial hypertension;
burns and extensive lesions of soft tissues;
dysentery, others intestinal diseases;
intestinal obstruction;
increased activity infections of the digestive tract;
endocrine diseases;
diabetes;
extensive pathologies of the liver, kidneys;
state of shock and sepsis.

Symptoms of high blood urea

When urea rises, the patient at first does not even know about the pathological process of his own body. He often complains of increased fatigue, but does not fully understand the cause of its origin. If the symptoms are constantly increasing, this may indicate a neglected clinical picture. In order not to bring your condition to extremes, you need to find out the main symptoms of an increase in urea in the blood:

anuria;
headache;
visual impairment;
the appearance of edema;
promotion blood pressure;
tendency to bleeding;
elevated symptoms dyspepsia;
nausea, vomiting;
decline in performance;
chronic diarrhea.

How to lower uric acid in the blood

If you determine the causes, how to treat high urea, the doctor will tell you. To reduce uric acid in the blood, the first step is to change the daily diet - to control the increased intake of protein from food. In addition, it is important to change the usual way of life, as an option - to avoid stress, prevent overwork, maintain water-salt balance.

Medications to take when running clinical pictures, at first, it is possible to correct endocrine disorders by taking a decoction of wild rose and diuretic teas. The main challenge is to ensure sustainable diuretic effect to eliminate the causes of an increase in the characteristic blood index. More serious medicines are determined by the doctor, he will also tell you how to treat the disease in order to productively get rid of all unpleasant symptoms.

Urea and creatinine are completely dependent on the food consumed, therefore, with an increase in the indicated value, you should not immediately look for global causes. Before treatment, it is necessary to pass the analysis again, to undergo advanced diagnostics. If urea is still elevated, does not correspond to the normal range, it's time to look for the main cause of the pathology.

Video: what is urea in a biochemical blood test

Among the indicators biochemical analysis blood urea is often determined. Why it can be increased and what consequences it leads to for a person - read the article.

Where is urea formed

Any substances that enter the body are broken down. Useful components - amino acids, fatty acids, glucose - are safely absorbed into the blood and absorbed. But the waste products of digestion also enter the bloodstream. After complete processing of proteins, nitrogenous residues remain - slag that is useless for the body.

Urea in the human body is formed during the breakdown of proteins. It is a compound of poisonous ammonia, which is neutralized in the liver by carbon and oxygen. Urea is filtered from the blood in the kidneys.

It is excreted in the urine, so the latter has a specific smell, due to nitrogen in the urine.

Normal values

Donate blood for biochemical analysis for urea in the morning. It is best to do this on an empty stomach - so the result will be reliable. If dynamic tracking is required, analyzes are taken in the same laboratory. This is due to the possibility of using different reagents. Therefore, the result will differ depending on the laboratory.

Concentration change

A blood urea test is ordered by any outpatient doctor, most often a general practitioner or physician general practice. This indicator of kidney function is never evaluated on its own.

It is included in a complex of biochemical indicators and is determined simultaneously with others:

Most often, together with urea, creatinine is determined - a substance that is also filtered in the kidneys.. Together they allow you to determine the glomerular filtration rate. This is the amount of blood that the kidneys can filter. Normal glomerular filtration rate exceeds 90 ml/min.

Meaning of concentration change

The fact that this formation of urea occurs in the liver and is filtered by the kidneys reflects the state of these two organs. With a moderate increase in its level, we can talk about a problem with the liver. A significant increase in urea indicates a poor filtration function of the kidneys.. They do not allow nitrogenous slags to pass into the urine, due to which their amount in the blood is steadily increasing.

Medications that affect concentration

Not always what causes urea to rise is associated with a disease.

Many drugs have a nephrotoxic effect of varying degrees of severity. They inhibit kidney function, resulting in elevated level urea.

Other drugs can slow down the formation of nitrogenous slags, reducing their amount.

Apart from medicines, there are other non-pathological causes that can affect the level of urea in the blood. You should be aware of this and warn the attending physician if urea was elevated in the screening analysis.

Circumstances that affect the urea content:

Physical activity the day before;
Psycho-emotional stress;
Overeating foods containing animal protein;
Starvation.

Change in concentration in certain groups of people

FROM special attention refer to the determination of the concentration of urea in the blood of pregnant women. Functionally, their kidneys are under great strain. Therefore, at any moment their work can slow down. This is manifested by an increase in the concentration of renal indicators: creatinine and urea.

During pregnancy, a woman is repeatedly asked to donate blood for full complex biochemical indicators. Combined with general clinical analyzes this will determine how healthy the kidneys are.

During pregnancy, there is a risk of developing a condition such as preeclampsia of pregnancy. This is a special type of nephropathy - kidney damage. If the symptoms of preeclampsia appeared against the background of increased urea, then kidney function decreases.

A lot of attention deserves the measurement of urea in the elderly. As we age, kidney function suffers. They lose their working elements - nephrons. As healthy kidney tissue is lost, urea levels rise. Given the weakness of the functions of all organs, the level of urea in the elderly is allowed to be slightly higher than in adults.

Increasing concentration

The reasons for the increase in urea are different. They can affect both the kidneys and other organs. That is why simple analysis means little and is practically not carried out separately for urea.

All diseases with increased urea are fundamentally divided into two groups:

Associated with increased protein breakdown;
Associated with impaired urea excretion.

In the pathogenesis of the first group of diseases, the excessive breakdown of proteins into amino acids plays a role. During this accelerated decomposition, a lot of ammonia is released. In the future, after passing through the liver, it will become urea.

These are the following pathologies:

All infections with fever;
internal bleeding;
Intestinal obstruction;
Burns and burn disease;
Sepsis;
Tumors of the blood system - lymphoma, myeloma.

The second group of pathologies is mainly problems of the urinary system. Slowing down the excretion of urea leads to its high level in the blood, even if the formation occurs in the usual amount.

This leads to the following conditions associated with a violation of the excretory function of the kidneys:

Chronic glomerulonephritis;
Chronic pyelonephritis;
Amyloidosis;
Congenital anomalies in the development of the kidneys;
Chronic kidney disease from stage 2;
Urolithiasis disease;
Kidney neoplasms.

Special mention should be made of elevated content urea in acute renal failure. it emergency, which develops in a few minutes or hours.

Therefore, it is important to notice the first manifestations of acute renal failure in time.

It may be caused by:

Poisoning with poisons;
Bleeding;
Traumatic shock;
Cardiogenic shock;
Infectious-toxic shock;
Syndrome of long compression.

Uremia

A significant increase in urea in the blood is called uremia. This is the final stage of development chronic illness kidneys and renal failure.

Uremia is a consequence of kidney pathology, but is manifested by disorders from other organs:

severe weakness;
Lack of appetite;
Increased bleeding;
The development of pleurisy, pericarditis.

Treat such severe kidney failure with dialysis several times a week for life.

Dialysis may be:

Peritoneal- using your own peritoneum;
extracorporeal- using a hemodialysis machine.

Video: Urea in the blood is increased. Causes and treatment of kidney failure

Causes of low urea

Most often, changes in the concentration of urea in the blood serum occur in the direction of increase. But sometimes the opposite situation occurs, when the amount of urea in the blood decreases. The sources of this state are discussed in the table.

Ways to deal with high urea

By itself, an increase in urea is not a disease. This is a symptom to be considered along with the underlying pathology.

But there is general principles, which should be observed if a person has an increased concentration of urea:

Reduce the amount of protein food;
Increase the amount of plant foods in the diet;
Avoid psycho-emotional overstrain;
Not to starve;
Timely treatment of infectious diseases.

Determination of the concentration of urea in the blood is widely used in diagnostics, used to assess the severity pathological process, to monitor the course of the disease and evaluate the effectiveness of the treatment. However, we should not forget that the level of urea in the blood can be affected not only by pathological, but also physiological factors(nature of nutrition, exercise stress etc.), as well as taking medications. The level of urea can change both upward and downward. At physiological processes the degree of deviation of the urea level from the norm, as a rule, is insignificant, while significant changes are observed in pathology, and the degree of change in the level of urea depends on the severity of the pathological process.

Normal values of urea in the blood

The concentration of urea in the blood serum of healthy adults is 2.5 - 8.3 mmol / l (660 mg / l). In women, compared with adult men, the concentration of urea in the blood serum is usually lower. In the elderly (over 60 years of age), there is a slight increase in the concentration of urea in the blood serum (by about 1 mmol / l compared with the norm of healthy adults), which is due to a decrease in the ability of the kidneys to concentrate urine in the elderly.

In children, the level of urea is lower than in adults, however, in newborns in the first 2–3 days, its content can reach the level of an adult (manifestation of physiological azotemia due to increased catabolism against the background of insufficient fluid intake in the first 2–3 days of life and low level glomerular filtration). Under conditions of hyperthermia, exicosis, urea figures can increase even more. Normalization occurs by the end of the first week of life. The level of urea in the blood of preterm infants 1 week. - 1.1 - 8.9 mmol / l (6.4 - 63.5 mg / 100 ml), in newborns - 1.4 - 4.3 mmol / l (8.6 - 25.7 mg / 100 ml ), in children after the neonatal period - 1.8 - 6.4 mmol / l (10.7 - 38.5 mg / 100 ml).

Increasing the level of urea in the blood

An increase in the level of urea in the blood is observed with:

eating excessive amounts of protein (as a result of increased urea synthesis);
a diet poor in chloride ions (compensatory, adaptive reaction aimed at maintaining the colloid osmotic pressure of the blood);
dehydration of the body: indomitable vomiting, profuse diarrhea, etc. (due to increased passive reabsorption in the renal tubules);
taking certain drugs: sulfonamides, chloramphenicol, tetracycline, gentamicin, furosemide, isobarine, dopegyt, nevigramone, lasix, anabolic steroids, corticosteroids, thyroxine in in large numbers;
excessive protein catabolism: leukemia, parenchymal jaundice, severe infectious diseases, intestinal obstruction, burns, dysentery, shock;
impaired urea excretion associated with kidney disease and urinary tract: chronic diseases kidneys (glomerulonephritis, pyelonephritis); obstruction of the urinary tract (tumors of the urinary tract, prostate gland, kidney stone disease); acute and chronic renal failure;
violation of the excretion of urea in diseases and conditions not associated with diseases of the kidneys and urinary tract: insufficiency of the heart, acute myocardial infarction; diabetes mellitus with ketoacidosis, Addison's disease and other diseases.

An increase in the level of urea in the blood, associated with its increased formation or a decrease in its filtration in the kidneys as a result of hemodynamic disturbances, as a rule, does not reach large values, the urea content usually does not exceed 13 mmol / l.

Large values blood urea levels are observed in kidney disease. Thus, the concentration of urea in the blood plasma of patients with chronic renal failure can reach 40.0 - 50.0 mmol / l. A particularly high content of urea (49.8 - 81.0 mmol / l and above) is observed in acute renal failure. At the same time, the excretion of urea in the urine is sharply reduced. However, it should be noted that an increase in the urea content is not early sign kidney dysfunction. It has been established that initially the level of uric acid increases, and then urea and creatinine, which is a threatening symptom. At various diseases kidneys, the degree of increase in the urea content is determined by the nature of the damage to the nephron, the level of intoxication, increased protein breakdown in the tissue (due to the restriction of protein in the diet of renal patients) and other factors. An increase in the content of urea in the blood up to 16.0 mmol / l is combined with impaired renal function moderate, up to 33.2 mmol / l - severe, over 49.8 mmol / l - a very severe disorder with a poor prognosis.

An increase in the content of urea in the blood, accompanied by a syndrome of intoxication, is called uremia. It is generally believed that urea is not toxic and that the intoxication syndrome that accompanies an increase in its content is due to the accumulation of other products in the body. At the same time, it should be borne in mind that urea, passing through the plasma membranes of cells relatively easily, being osmotically active substance, carries water into the cells of parenchymal organs. This leads to an increase in the volume of cells (cellular overhydration) and a violation of their functional state.

Decrease in the level of urea in the blood

A decrease in the content of urea in the blood is rarely observed:

during pregnancy (due to physiological hydremia);
on a diet with low content protein and high in carbohydrates, starvation;
at parenteral administration fluids (due to hyperhydration);
after hemodialysis;
with reduced protein catabolism;
when taking STH;
in violation of absorption in the intestine, celiac disease;
with increased protein utilization (in late dates pregnancy, in children under 1 year old, with acromegaly);
with congenital deficiency or lack of enzymes involved in the ornithine urea cycle;
with particularly severe liver damage ( liver failure), caused, in particular, by poisoning with phosphorus, arsenic and other hepatotropic poisons; acute liver necrosis, hepatic coma, decompensated cirrhosis, hepatitis (it is known that the liver has large functional reserves, its ability to deamination and urea synthesis is preserved when up to 85% of its tissue is excluded from metabolic processes).

Literature:

Tsyganenko A. Ya., Zhukov V. I., Myasoedov V. V., Zavgorodniy I. V. - Clinical Biochemistry - Moscow, "Triad-X", 2002
Slepysheva V. V., Balyabina M. D., Kozlov A. V. - Methods for the determination of urea
Clinical assessment laboratory tests - edited by N. U. Titz - Moscow, "Medicine", 1986
Kamyshnikov V. S. - A doctor's pocket guide to laboratory diagnostics- Moscow, MEDpress-inform, 2007
Marshall J. - Clinical Biochemistry - Moscow, St. Petersburg, "Binom", "Nevsky Dialect", 2000