What does a low specific gravity of urine indicate? Relative density of urine: deviations from the norm during analysis. General urinalysis: what kind of study is it?

Without exception, all diagnostic procedures carried out on a person cannot be done without testing. One of the most informative and simplest is a general urine test, which helps the doctor assess not only kidney function, but also tells about the condition of the entire body. One of the fundamental indicators of this analysis is the specific gravity of urine, the norm of which will be discussed below. This indicator determines the ability of the kidneys to filter and remove secondary urine.
Various types of abnormalities in the examination will help to detect various pathologies and begin prompt treatment.

The essence of the analysis

The specific gravity of urine is normally a determining factor in assessing the ability of the kidneys to produce urine of greater or lesser concentration. This biological substance is formed in several stages.

Filtration of blood in glomerular structures with the formation of primary urine, very similar to plasma. The difference is that plasma protein and carbohydrate particles are much larger. Up to 160 liters of such liquid are formed per day.
Sedimentation of urine into the kidney tubules, where all necessary substances are reabsorbed.
Formation of secondary urine from the remaining fluid containing waste.

This produces urine that is released out. It has a liquid part and a dry residue, which contains a number of components determined in OAM.

Urea.
Salt crystals of uric acid.
Sulfate salts.
Chlorides.
Ammonia ions.

It doesn’t matter how many fluids enter the body during the day, all metabolic products are eliminated. If a person drinks little, the urine will simply be more concentrated. If the patient drinks a lot, then there will be little dry residue, and the urine will be diluted, since the kidneys remove not only by-products, but also excess water.

Carrying out analysis

Determination of density is carried out using a urometer apparatus. Urine along the wall is placed in a special cylinder; if the process is accompanied by the appearance of foam, then it must be removed. The entire cylinder is placed in the device. It should be noted that if the patient cannot go to the toilet himself, then urine must be collected with a catheter.
The density is determined by the level of the underlying meniscus of the apparatus scale; therefore, the cylinder and the apparatus should not be in contact.
There are situations when the volume of urine obtained is too small, then it is diluted with distilled water and all calculations are made taking into account the degree of dilution.
And so, when diagnosing using this method, qualitative and quantitative indicators are taken into account. A mixture of chloroform and benzene is placed in a cylinder, and a drop of the test liquid is dropped into it. If she drowned, then the urine density is too high, if she floated, then it is low. By adding each of the components in parts, they ensure that the material under study is in the middle of the liquids. The density of the urine will be equal to the density of the resulting solution.
It is worth remembering that the urometer was calibrated at 15 C, which means that it is necessary to make an adjustment for the ambient temperature. At high temperatures, a person always drinks more and loses more fluid, and at low temperatures, he consumes very little fluid. All this, of course, influences, and daily changes in density.

Normal Specific Gravity Values

As mentioned above, this indicator determines the activity of the kidneys to dilute or concentrate urine. It depends on the amount drunk, spent and on the ambient temperature. There are even a number of factors that predispose to changes in specific gravity.

The patient's consumption of salt, fatty and fried foods.
Change in the amount you drink.
Strong sweating due to various reasons.
Separation of fluid during breathing.

Urine analysis, the specific gravity of which varies from 1.010 to 1.025, is normal for an adult. In children, the density differs somewhat from that in adults and is related to age. As soon as the child is born, its indicator has the lowest value and is 0.010. As the baby grows, the density of his urine increases. It is worth noting that the time of day is also reflected in the indicator. For example, in the morning the density is highest, since there is the greatest amount of dry sediment at the moment.

Deviation from normal indicators

There are two types of changes in this indicator.
1. Specific gravity exceeds the norm
An increase in urine concentration is a consequence of certain pathological processes.

Increasing edema occurs, which is caused by glomerulonephritis or insufficient renal function.
Various pathologies of hormonal origin.
Excessive loss of fluid from the body due to burns, vomiting, diarrhea, and blood loss.
Damage to abdominal organs and intestinal obstruction.
Vomiting in pregnant women.
High doses of antibiotics.
Kidney pathologies of an acute or chronic nature.

There are many factors that increase the density of urine. These may be metabolic disorders or diseases of the reproductive and urinary apparatus. This phenomenon can also be observed with physiological changes - increased sweating and thirst after eating salt.
Oddly enough, the increased specific gravity of urine has its own clear manifestations

The volume of urine is reduced.
Urine has a darker color.
The smell of urine is quite unpleasant.
The appearance of edema is noted.
The patient begins to experience swelling.
The patient is weak, drowsy and prone to getting tired quickly.
Pain in the lower back and abdomen is common.

In children, increased density may occur due to the presence of pathologies that are congenital or acquired. Very often, children are affected by intestinal infections due to weak immunity, and in case of poisoning, as is known, a lot of fluid is lost.
You can separately consider diabetes mellitus, in which an increase in the weight of urine is based on the high content of sugars in it. Or if there is protein and breakdown products in the urine. Urine will be denser. To identify any such pathology, certain tests must be carried out.

2. Reduced relative density
Sometimes, after any illness, the doctor recommends that the patient consume more water and other drinks to quickly remove toxins and replenish fluid balance. Such replenishment will most likely reduce the concentration of dry sediment and dilute the urine; such dilution is physiological in nature. It is also considered normal for a decrease in urine concentration in the heat, when a person drinks a lot, or when taking diuretics.
There are a number of reasons that cause pathological dilution.

Neurogenic diabetes, characterized by a decrease in the synthesis of pituitary hormones.
Nephrogenic diabetes, which occurs when nephron cells become tolerant to antidiuretic hormone.
Diabetes that occurs during pregnancy.
Nervous disorders due to stress and depression.
Inflammation of the kidney tubules.

The condition of reduced density (hyposthenuria) requires diagnostic measures, as it can have quite serious causes.
For further diagnosis, it is necessary to prescribe tests that determine exactly the functional component. Zimnitsky test, carried out in drinking mode and concentration test.
It is worth remembering that if the change in night density is permanent, you need to urgently consult a doctor who will help you deal with the problem and find its cause.

Today, not a single patient examination is complete without laboratory tests, which include a general urine test. Despite its simplicity, it is very indicative not only for diseases of the genitourinary system, but also for other somatic disorders. The specific gravity of urine is considered one of the main functional indicators of kidney function and allows one to evaluate their filtration function.

Urine formation

Urine in the human body is formed in two stages. The first of these, the formation of primary urine, occurs in the glomerulus, where blood passes through numerous capillaries. Since this is carried out under high pressure, filtration occurs, separating blood cells and complex proteins that are retained by the walls of the capillaries, from water and molecules of amino acids, sugars, fats and other waste products dissolved in it. Further, following the nephron tubules, primary urine (from 150 to 180 liters can be formed per day) undergoes reabsorption, that is, under the influence of osmotic pressure, water is again absorbed by the walls of the tubules, and the useful substances contained in it again enter the body due to diffusion. The remaining water with urea, ammonia, potassium, sodium, uric acid, chlorine and sulfates dissolved in it is secondary urine. It is this that passes through the collecting ducts, systems of small and large renal calyces, renal pelvis and ureter into the bladder, where it accumulates and is then released into the environment.

How is specific gravity determined?

To determine the density of urine in the laboratory, a special device is used - a urometer (hydrometer). To carry out the examination, urine is poured into a wide cylinder, the resulting foam is removed with filter paper and the device is immersed in the liquid, being careful not to let it touch the walls. After stopping the immersion of the urometer, lightly press on it from above and, when it stops oscillating, mark the position of the lower meniscus of urine on the scale of the device. This value will correspond to the specific gravity. When carrying out measurements, the laboratory technician must also take into account the temperature in the room. The fact is that most urometers are calibrated to operate at a temperature of 15°. This is due to the fact that as the temperature rises, the volume of urine increases and, accordingly, its concentration decreases. When decreasing, the process goes in the opposite direction. In order to remove this error? for every 3° above 15°, 0.001 is added to the obtained value and, accordingly, for every 3° below, the same value is subtracted.

Normal specific gravity values

The relative density indicator (this is another name for specific gravity) characterizes the ability of the kidney, depending on the body’s needs, to dilute or concentrate primary urine. Its value depends on the concentration of urea and salts dissolved in it. This value is not constant, and during the day its indicator can change significantly under the influence of food, drinking regimen, and the processes of fluid excretion through sweat and breathing. For adults, the normal specific gravity of urine will be 1.015-1.025. The density of urine in children is slightly different from that of adults. The lowest numbers are recorded in newborns in the first days of life. For them, the specific gravity of urine can normally vary from 1.002 to 1.020. As the child grows, these indicators begin to increase. Thus, for a five-year-old child, values from 1.012 to 1.020 are considered normal, and the specific gravity of urine in children 12 years old is practically no different from the values in adults. It is 1.011–1.025.

If the specific gravity of urine is low

Hyposthenuria, or a decrease in specific gravity to 1.005-1.010, may indicate a decrease in the concentrating ability of the kidneys. It is regulated by antidiuretic hormone, in the presence of which the process of water absorption occurs more actively, and accordingly, a smaller amount of more concentrated urine is formed. And vice versa - in the absence of this hormone or in small quantities, urine is formed in large volumes, which have a lower density. The following conditions may cause low specific gravity of urine:

diabetes insipidus;

acute pathology of the renal tubules;

chronic renal failure;

polyuria (large volume of urine excreted) caused by drinking too much, taking diuretics, or resolving large exudates.

Why is the specific gravity decreasing?

It is customary to identify three main reasons leading to a pathological decrease in specific gravity.

Polydipsia is excessive water consumption, which leads to a decrease in the concentration of salts in the blood plasma. In order to compensate for this process, the body increases the formation and excretion of urine in large volumes, but with a reduced salt content. There is such a pathology as involuntary polydipsia, in which there is a low specific gravity of urine in women with an unstable psyche.

Causes having extrarenal localization. These include neurogenic diabetes insipidus. In this case, the body loses the ability to produce antidiuretic hormone in the required quantities and, as a result, the kidneys lose the ability to concentrate urine and retain water. The specific gravity of urine may decrease to 1.005. The danger with this is that even with a decrease in water intake, the amount of urine does not decrease, which leads to dehydration. This group of causes also includes damage to the hypothalamic-pituitary region due to injury, infection or surgery.

Causes related to kidney damage. Low specific gravity of urine often accompanies diseases such as pyelonephritis and glomerulonephritis. This group of pathologies also includes other nephropathies with parenchymal lesions.

Hypersthenuria, or increased specific gravity of urine, can usually be observed with oliguria (decreased volume of urine excreted). It can occur due to insufficient fluid intake or large fluid losses (vomiting, diarrhea), or with increasing edema. Also, increased specific gravity can be observed in the following cases:

in patients with glomerulonephritis or cardiovascular insufficiency;

with intravenous administration of mannitol, radiopaque agents;

when removing certain medications;

increased specific gravity of urine in women may occur due to toxicosis of pregnant women;

against the background of proteinuria in nephrotic syndrome.

Separately, it is necessary to mention the increase in urine density in diabetes mellitus. In this case, it may exceed 1.030 against the background of an increased volume of urine excreted (polyuria).

Functional tests

To determine the functional state of the kidneys, it is not enough just to do a urine test. Specific gravity can change throughout the day, and in order to accurately determine how much the kidneys are able to secrete or concentrate substances, functional tests are performed. Some of them are aimed at determining the state of the concentration function, others - the excretory function. It often happens that disturbances affect both of these processes.

Dilution test

The test is carried out while the patient is in bed rest. After an overnight fast, the patient empties his bladder and drinks water within 30 minutes at the rate of 20 milliliters per kilogram of his weight. After all the liquid has been drunk and then 4 times at intervals of one hour, urine is collected. After each urination, the patient additionally drinks the same volume of liquid that was excreted. The quantity and specific gravity of the selected samples are assessed.

If in healthy people the specific gravity of urine (normal) in women and men should not fall below 1.015, then against the background of water load the density can be 1.001-1.003, and after its removal it increases from 1.008 to 1.030. In addition, during the first two hours of the test, more than 50% of the liquid should be released, and at the end of the test (after 4 hours) - more than 80%.

If the density exceeds 1.004, then we can talk about a violation of the dilution function.

Concentration test

To conduct this examination, drink and liquid food are excluded from the patient’s diet for a day and food high in protein is included. If the patient suffers from severe thirst, drinking in small portions is allowed, but not more than 400 ml per day. Every four hours, urine is collected, assessing its quantity and specific gravity. Normally, after 18 hours without fluid intake, the relative density should be 1.028-1.030. If the concentration does not exceed 1.017, then we can talk about a decrease in the concentration function of the kidneys. If the indicators are 1.010-1.012, then isosthenuria is diagnosed, that is, the complete loss of the kidney’s ability to concentrate urine.

Zimnitsky test

The Zimnitsky test allows you to simultaneously evaluate both the ability of the kidneys to concentrate and the ability to excrete urine and do this against the background of a normal drinking regimen. To carry it out, urine is collected in portions every 3 hours during the day. In total, 8 portions of urine are obtained per day, in each of which the quantity and specific gravity are recorded. Based on the results, the ratio of nighttime and daytime diuresis is determined (normally it should be 1:3) and the total amount of fluid excreted, which, along with monitoring the specific gravity in each portion, makes it possible to assess kidney function.

The specific gravity of urine (the norm for women and men is given above) is an important indicator of the ability of the kidneys to function normally, and any deviation makes it possible to identify the problem in time and take the necessary measures with a high degree of probability.

In the article you will read what indicators are included in a general urine analysis, what are the reference intervals for these indicators, what is the norm of leukocytes and red blood cells in the urine, how much protein and sugar can be in the urine, what epithelial cells are found in the analysis.

The information was prepared by doctors from CIR laboratories and clinics.

A general clinical examination of urine (general urinalysis, OAM) includes the determination of physical properties, chemical composition and microscopic examination of sediment.

Physical properties of urine

The main physical properties of urine determined in OAM:

transparency
specific gravity
pH (urine reaction)

Urine color

The color of urine normally ranges from light yellow to deep yellow and is due to the pigments it contains (urochrome A, urochrome B, uroethrin, uroresin, etc.).

Reference values:

Interpretation

The intensity of the color of urine depends on the amount of urine excreted and its specific gravity. Rich yellow urine is usually concentrated, excreted in small quantities and has a high specific gravity. Very light urine is slightly concentrated, has a low specific gravity and is excreted in large quantities.

Discoloration may be the result of a pathological process in the urinary system, the effects of dietary components, or medications taken.

Transparency (turbidity)

Normal urine is clear. Cloudiness of urine can be the result of the presence of red blood cells, leukocytes, epithelium, bacteria, fat droplets, precipitation of salts, pH, mucus, urine storage temperature (low temperature promotes the precipitation of salts).

In cases where the urine is cloudy, you should find out whether it is immediately cloudy, or whether this cloudiness occurs some time after standing.

Specific gravity of urine (g/l)

In a healthy person, it can fluctuate over a fairly wide range throughout the day, which is associated with periodic food intake and loss of fluid through sweat and exhaled air.

Interpretation

The specific gravity of urine depends on the amount of substances dissolved in it: urea, uric acid, creatinine, salts.

A decrease in the specific gravity of urine (hyposthenuria) to 1005-1010 g/l indicates a decrease in the concentrating ability of the kidneys, an increase in the amount of urine excreted, and drinking plenty of fluids.
An increase in the specific gravity of urine (hypersthenuria) of more than 1030 g/l is observed with a decrease in the amount of urine excreted, in patients with acute glomerulonephritis, systemic diseases, and cardiovascular failure; it may be associated with the appearance or increase of edema, large loss of fluid (vomiting, diarrhea ), toxicosis of pregnant women.

Urine reaction (pH)

The pH of urine in a healthy person on a mixed diet is acidic or slightly acidic.

Interpretation

The urine reaction may vary depending on the nature of the food. The predominance of animal proteins in the diet leads to a sharply acidic reaction; with a vegetable diet, the urine reaction is alkaline.

An acidic urine reaction is observed with fevers of various origins, diabetes mellitus in the stage of decompensation, fasting, and renal failure.
An alkaline reaction of urine is characteristic of cystitis, pyelonephritis, significant hematuria, after vomiting, diarrhea, and drinking alkaline mineral water.

Chemical examination of urine

Currently, chemical testing of urine is carried out on automatic analyzers using the dry chemistry method.

Chemical testing includes determination in urine:

squirrel
glucose
ketone bodies

Protein in urine, normal protein in urine

Normal urine contains a very small amount of protein (less than 0.002 g/l), which is not detected by qualitative samples, so it is considered that there is no protein in the urine. The appearance of protein in the urine is called proteinuria.

Interpretation

Physiological proteinuria includes cases of temporary appearance of protein in the urine that are not associated with diseases. Such proteinuria is possible in healthy people after eating a large amount of protein-rich food, after severe physical stress, emotional experiences, and epileptic seizures.

Functional proteinuria associated with hemodynamic stress can occur in children with fever, emotional stress, congestive heart failure or hypertension, or after cooling.

Pathological proteinuria is divided into renal (prerenal) and extrarenal (postrenal):

Extrarenal proteinuria is caused by an admixture of protein secreted by the urinary tract and genitals; they are observed in cystitis, pyelitis, prostatitis, urethritis, vulvovaginitis. Such proteinuria rarely exceeds 1 g/l (except for cases of severe pyuria - detection of a large number of leukocytes in the urine).
Renal proteinuria is most often associated with acute and chronic glomerulonephritis and pyelonephritis, nephropathy in pregnancy, febrile conditions, severe chronic heart failure, renal amyloidosis, lipoid nephrosis, renal tuberculosis, hemorrhagic fevers, hemorrhagic vasculitis, hypertension.

False-positive results when using test strips can be caused by severe hematuria, increased density (more than 1.025) and pH (above 8.0) of urine.

Determination of glucose (sugar). Normal level of glucose in urine.

Also, urine normally contains traces of glucose not exceeding 0.02%, which, like protein, is not detected by ordinary qualitative tests.

Interpretation

The appearance of glucose in the urine (glucosuria) can be physiological and pathological.

Physiological glucosuria is observed when eating large amounts of carbohydrates (alimentary glucosuria), after emotional stress (emotional glucosuria), after taking certain medications (caffeine, glucocorticoids), and in case of poisoning with morphine, chloroform, phosphorus.
Pathological glucosuria can be of pancreatic origin (diabetes mellitus), thyroid (hyperthyroidism), pituitary (Ishchenko-Cushing syndrome), hepatic (bronze diabetes). To correctly assess glucosuria, it is necessary to determine the amount of sugar in daily urine, which is especially important in patients with diabetes.

Ketone bodies in urine

Ketone bodies (acetone, acetoacetic acid, (B-hydroxybutyric acid)) can sometimes be detected in the urine of a healthy person with a very small intake of carbohydrates and a large amount of fats and proteins.

Interpretation

Ketone bodies appear in the urine during fasting, alcohol intoxication, diabetes mellitus, in children with vomiting and diarrhea, neuro-arthritic diathesis, as well as during severe infectious processes accompanied by a prolonged increase in temperature.

Microscopic examination of urine

Microscopic examination of urine sediment is carried out after determining the physical and chemical properties of urine. The sediment for research is obtained by centrifugation of urine.

There are two types of urine sediment:

organized (erythrocytes, leukocytes, epithelial cells, casts) sediment
unorganized sediment (salts, mucus).

Organized sediment

Organized sediment is represented by:

In addition, the sediment may contain: sperm, bacteria, yeast and other fungi.

Reference values (in view):

sediment element		from 0 to 18 years		over 18 years old
sediment element		boys	girls	men	women
red blood cells		single in the preparation		0 - 2
leukocytes		0 - 5	0 - 7	0 - 3	0 - 5
altered leukocytes		none
epithelial cells	flat	single in the preparation		0 - 3	0 - 5
	transitional	0 - 1
	renal	none
cylinders	hyaline	none
	grainy
	waxy
	epithelial
	erythrocyte

Interpretation

Red blood cells in urine

Normally, there are no red blood cells in urine sediment, or only a few in the specimen. Most often, hematuria is associated with a pathological process of various etiologies (autoimmune, infectious, organic damage) directly in the kidneys. If red blood cells are detected in the urine, even in small quantities, further observation and repeated studies are always necessary.

Leukocytes in urine

Normally, there are no leukocytes in the urine, or only a few are detected in the specimen and in the field of view. Leukocyturia (more than 5 leukocytes in the field of view) can be infectious (bacterial inflammatory processes of the urinary tract) and aseptic (with glomerulonephritis, amyloidosis, chronic rejection of a kidney transplant, chronic interstitial nephritis). Pyuria is considered to be the detection of 10 or more leukocytes in the field of view in sediment by microscopy.

Active leukocytes (Sternheimer–Malbin cells) are normally absent. The detection of active leukocytes in the urine indicates an inflammatory process in the urinary system, but does not indicate its localization.

Epithelium in urine

In healthy people, in the urine sediment, single cells of squamous (urethra) and transitional epithelium (pelvis, ureter, bladder) are found in the field of view. Renal (tubules) epithelium is absent in healthy people.

Flat epithelium: in men, only single cells are normally detected, their number increases with urethritis and prostatitis. In the urine of women, squamous epithelial cells are present in greater numbers.

Transitional epithelial cells: may be present in significant numbers during acute inflammatory processes in the bladder and renal pelvis, intoxication, urolithiasis and neoplasms of the urinary tract.

Renal epithelial cells: appear with nephritis, intoxication, circulatory failure. The appearance of renal epithelium in very large quantities is observed during necrotic nephrosis (for example, in case of poisoning with sublimate, antifreeze, dichloroethane, etc.).

Casts in urine

Normally, urine sediment may contain hyaline casts (single in the specimen). Granular, waxy, epithelial, erythrocyte, leukocyte casts and cylindroids are normally absent. The presence of casts in the urine (cylindruria) is the first sign of a reaction from the kidneys to a general infection, intoxication, or to the presence of changes in the kidneys themselves.

Bacteria in urine

Bacteria are normally absent or their number does not exceed 2000 cells per 1 ml. Bacteriuria is not absolutely reliable evidence of an inflammatory process in the urinary system. The microbial content is of decisive importance. When examining a general urine test, only the fact of the presence of bacteriuria is stated.

Unorganized sediment

Unorganized sediment includes salt crystals, as well as mucus and crystals of cystine, tyrosine and lecithin found in pathological urine. The precipitation of salts depends mainly on the properties of urine, in particular on its pH. This parameter has little diagnostic value. An increase in the content of inorganic salts in the urine indirectly indicates urolithiasis with stones of the appropriate composition.

In acidic urine there are:

uric acid;
urates (urate salts, which include sodium urate, calcium, potassium, magnesium);
oxalates (calcium oxalate, calcium carbonate).

Alkaline urine contains:

tripelphosphates (ammonium phosphate-magnesium);
phosphates;
ammonium urate.

Today, a very important factor in establishing an accurate diagnosis of a patient is a clinical urine test. Its quantity and composition indicate the functioning of the urinary system and the functioning of other body systems. The indicators of a healthy person are regulated by certain standards, deviation from which indicates a particular violation. One of the important points when conducting the study is the specific gravity of urine.

It is carried out in the kidneys in two stages. At the first stage, the formation of the so-called from circulating blood occurs. Its volume can reach up to 150 liters. Then, through filtration, all the beneficial substances from it are absorbed into the body, and the remaining liquid is excreted out - this is secondary urine, the specific gravity of which is determined. It contains substances such as urea, sodium and potassium salts.

In general, the specific gravity test shows the functioning of the kidneys. Suspensions in urine and its concentration will depend on the ability of the kidneys to remove metabolic products. With the liquid entering the human body, metabolic products enter. If the amount of this liquid is not enough, then the kidneys excrete a small proportion of these elements into the urine and its specific gravity becomes large. With a significant volume of liquid, the amount of urine, on the contrary, increases, but the concentration of trace elements in it decreases.

The value of urinary density is determined by the content of salts and urea in it.

The determination of the normal urine concentration is carried out by a laboratory assistant. The numbers may vary slightly throughout the day, as this is affected by the amount of fluid you drink and the amount of salt in the food you eat. For a more accurate result, it is recommended to submit morning urine for testing.

Normal urine density:

adult – 1015-1028;
children (up to 12 years) - 1002-1020, in newborns it reaches 1016-1018;
in pregnant women – 1011-1030.

A decrease in urine density is called hyposthenuria and is diagnosed when the level drops to 1005. Low specific gravity of urine occurs when the concentration function of the kidneys is weak, which is regulated by antidiuretic hormones. Its presence ensures active absorption of water, so urine is weakly concentrated. If there is no antidiuretic hormone or there is too little of it, then urine is formed in large quantities, and its specific gravity decreases. There are quite a few reasons for the decline, and this happens not only due to kidney failure.

A large amount of water consumed by a person contributes to pathological hyposthenuria. This factor, accordingly, leads to an increase in blood plasma volume. To compensate, the body produces more urine than usual to flush out excess fluid. At the same time, its consistency decreases and the composition is diluted. Another reason may be endocrine disorders of the body, as a result of which the production of the hormone vasopressin, necessary for regulating the homeostasis of the body, is disrupted.

Very often pregnant women experience hyposthenuria. Low concentration of urine during pregnancy may be due to hormonal changes in a woman’s body, with severe toxicosis. Also in this condition there is a high risk of developing kidney pathologies, which affects the process of urine formation.

A newborn baby has a low urine specific gravity, but after a few weeks it returns to normal. The amount of urine in children differs from that in adults, which should be taken into account when conducting a clinical analysis.

Sometimes there is a high specific gravity of urine - this is referred to as hypersthenuria. This condition develops with a small amount of urine, the cause of which is insufficient fluid intake. This may be a consequence of severe poisoning, accompanied by frequent vomiting and loose stools. In case of cardiovascular failure, the weight of urine will also be increased, since the heart does not process all the incoming fluid and tissue swelling appears.

Possible disorders with low or high specific gravity of urine

This laboratory test shows both kidney function and some other abnormalities in the body. If the specific gravity of urine is low, the doctor may suggest the following diseases:

Diabetes.
Kidney failure.
Chronic pyelonephritis.
Nephrosclerosis.
Chronic nephritis.
Acute glomerulonephritis.

It is necessary to distinguish from these diagnoses the characteristics of each patient. For example, it is possible to reduce the concentration of urine by drinking plenty of water, taking diuretics, and also if you had an inflammatory disease the day before the study.

The pathogenesis of the cause of low urine weight is an increase in fluid volume. In this regard, the concentration of salts in the blood plasma decreases. As a protective reaction, the body produces a lot of diluted urine. Patients suffering from hyposthenuria notice symptoms in the form of swelling throughout the body, pain in the lower abdomen, and a decrease in the daily amount of urine.

If the specific gravity of urine is increased and this is not related to the patient’s lifestyle, then the presence of the following diseases is concluded:

Diabetes. In this case, it is necessary to add other characteristic symptoms, and the density and weight of urine will reach 1050.
Violation of water-salt balance.
Dehydration due to severe vomiting due to poisoning.
A decrease in the amount of urine produced, which indicates poor kidney function.
Cardiovascular failure.
Liver diseases.
Toxicosis of pregnant women.

Since ideally the specific gravity indicators vary within certain limits, a deviation in one direction or another indicates a disease. The results are monitored strictly by the attending physician. After diagnosis and treatment, patients undergo a repeat test procedure, which shows the result of therapy.

Urine formation is an important indicator of human health and normal functioning of the body. Without a detailed examination of urine, not a single diagnostic conclusion can be made. However, deviations from standards do not always mean a serious pathology; the main thing is to seek help from a medical specialist in a timely manner.

The specific gravity of urine is determined as the ratio of its density to the density of simple distilled water. The density of urine is often not constant throughout the day because it depends on the total amount of fluid a person consumes as well as their metabolic rate.

However, the relative density of urine can provide doctors with some clues about problems occurring in the human body.

The specific gravity of urine is also called its relative density. These indicators indicate problems in the functioning of the kidneys, since these organs are responsible for diluting and concentrating urine.

When the body performs its functions normally, the relative density varies depending on the amount of food taken and the volume of liquid.

Fluctuations in the specific gravity of urine are detected using several types of tests. The most commonly used methods are: Zimnitsky's test, test with dry food and test with water load.

Only by assessing the density of urine excreted during the collection of each sample can average data be derived that will help doctors understand the reasons for the decrease or increase in urine density.

Norm and deviations

The process of urine density usually consists of three stages. The first one is filtration. Second stage - reabsorption. It involves the reverse process of absorption. It occurs in the nephron tubules into which urine flows.

Third stage - tubular secretion. During this process, toxic metabolic products are released from the blood under the influence of special enzymes.

Thus, substances that change its density enter the urine.

The specific gravity of urine varies depending on the total volume of substances that are dissolved in it. The higher the concentration of urine, the greater its density. The last indicator is determined by salts, as well as protein, leukocytes, bilirubin and others.

At different times of the day, normal density readings may vary from 1001 to 1040 g/l. Only a doctor can calculate deviations in this case by interviewing the patient and approximately finding out what is the reason for the increase or decrease in concentration.

If the analysis is carried out on the basis of a study of the morning urine sample, then its normal density varies from 1015 to 1020 g/l. However, in the morning urine can be very saturated, since liquid does not enter the human body at night.

Deviations in the density of urine can be caused not only by characteristics of the human body. Quite often, even simple seasonal changes can be the cause. In winter, the density of urine in a healthy person is usually lower, while in summer the density of urine is higher.

Specific gravity of urine 1010 g/l

A urine density of 1010 g/l is borderline. Quite often it is used as a guide.

If, upon receiving test results, the density of urine does not exceed 1010 g/l, this may indicate hyposthenuria.

If the density of urine more than 1010 g/l, this speaks of hypersthenuria.

If The density of urine and blood are the same- 1010 g/l, then the doctor may suspect isosthenuria.

Relative density in women

In women, unlike men, the density of urine is somewhat lower, but it can also fluctuate depending on the individual characteristics of the body during the day.

Normal urine density in women and girls over 12 years of age varies from 1010 to 1025 g/l.

Any changes in the density of urine should be discussed with your doctor, as they could be caused by external factors and are not the result of health problems.

In pregnant women

Pregnant women may experience an increase in urine density during toxicosis, when the body quickly loses fluid without having time to restore its balance. But a sharp decrease in density can also be noticeable, especially in those moments when the swelling that developed during the previous day subsides by morning.

If the expectant mother is not susceptible to toxicosis, usually the density of her urine may vary from 1010 to 1030 g/l. But this indicator is not a reference.

Normal indicators for a child under one year old

The density of urine in newborns is quite low. Indicators are considered normal from 1008 to 1018 g/l.

In six-month-old children, normal urine density values are within the range from 1002 to 1004 g/l.

In children from six months to one year, the indicators are considered normal. from 1006 to 1010 g/l.

It can be quite difficult to obtain the required amount of urine, especially in young children. A minimum of 50 ml of urine is required for the test.

Urine density in children aged 2 years

At the age of 2–3 years in children, the normal boundaries of urine density shift slightly. That is, indicators in the range of from 1010 to 1017 g/l.

But it is worth considering that, as in adults, these indicators can change throughout the day, as well as when consuming a large or insufficient amount of liquid.

In children from 3 years old

In children from 3 to 5 years old, density is considered the norm. from 1010 to 1020 g/l.

A child from 7 to 8 has normal density indicators - from 1008 to 1022 g/l.

Closer to 12 years, or more precisely from 10 to 12 years, the density of a child’s urine approaches normal levels for an adult. Indicators are considered normal from 1011 to 1025 g/l.

At the age of 12 years, the normal density of urine in a child becomes the same as in an adult, that is from 1010 to 1022 g/l.

If urine density is below normal

A decrease in urine density below the normal level of 1010 g/l indicates the following diseases:

diabetes insipidus;
renal failure.

In some cases, this effect occurs when taking diuretics and drinking plenty of fluids. Typically, a decrease in the specific gravity of urine is called hyposthenuria. This phenomenon implies a violation of the concentration function.

Hyposthenuria can also occur in healthy people, after nutritional dystrophy or when edema subsides.

If the density is higher than normal

If the density of urine is higher than normal, that is, above the upper limit of 1030 g/l, then there may be several reasons for this phenomenon.

First of all, these can be diseases such as:

diabetes;
glomerulonephritis;
pyelonephritis;
cystitis;
other kidney or urinary tract diseases.

Often, the density of urine increases in cases where a person takes antibiotics or diuretics in large dosages.

Also, increased density of urine is observed with low, insufficient fluid intake, with its sudden loss, due to vomiting, diarrhea or profuse sweating.

An increase in urine density is called hypersthenuria.