How is the density of urine determined and what does it show in adults and children: the norm and causes of deviations in the specific gravity of urine. Relative density of urine: normal specific gravity of urine in women and children

08.09.2019

Specific gravity(second name - relative density) of urine - an indicator that characterizes the work of the kidneys and makes it possible to assess how well they cope with the function of filtering and removing unnecessary compounds from the body.

By studying the density of the biological fluid, the laboratory assistant determines what is the content in it:

Creatinine.
Urea.
uric acid.
sodium and potassium salts.

It is by the values of these parameters that the above criterion is calculated.

Specific gravity of urine: normal indicators for men, women and children

Determination of the density of urine is carried out in a laboratory using a special device - urometer. In order for the data obtained to be true, the patient must correctly collect material for the study (do not drink alcohol the day before, a lot of liquid).

Slight fluctuations in the parameter during the day is a normal physiological reaction. This is due to changes that occur during eating, drinking water, doing heavy physical work, resting, sweating, etc. Under different conditions, the kidneys of a healthy person excrete urine, the density of which is normally equal to from 1.010 to 1.028.

In men and women who do not have diseases of the urinary system, with moderate physical exertion, the specific gravity of morning urine is most often from 1.015 to 1.020. As for children, their figure may be slightly lower.

For children, the norm option is from 1.003 to 1.025. In the first week of life, the specific gravity of the urine of the child should be within up to 1.018, starting from the second week and until the end of the second year - from 1.002 to 1.004.

Later, the indicator begins to rise and, during normal kidney function, is already from 1.010 to 1.017. In children 4-5 years of age, the density is 1,012-1,020 . For children over 10 years old, it should be in the range from 1.011 to 1.025.

Causes of a decrease in the specific gravity of urine

If the density of the biological fluid is below normal, they talk about hypostenuria. This does not necessarily mean that the person is sick. Physicians are aware of cases where such a deviation was the result of the patient drinking an excessive amount of liquid shortly before the laboratory test.

Also, the use of any diuretic drugs leads to hypostenuria. The doctor must be warned about this factor in advance so that the data obtained are not misinterpreted.

What diseases cause a decrease in the specific gravity of urine

If we talk about the pathological causes of hypostenuria, they are as follows:

Diabetes.
Polydipsia (usually seen in people with unstable mentality)
Neurogenic and nephrogenic diabetes insipidus.
Inflammation of the renal tubules.
The presence in the body of unresolved infiltrates.
Untreated or complicated pyelonephritis.
Chronic renal failure.
Compliance with an overly strict diet, lack of vitamins, trace elements and minerals in the diet.
The presence of nodular formations on the renal tissues.
Hormonal failure (typical for women of childbearing age, as well as during menopause).

Many patients with a significant decrease in the described indicator complain of:

The appearance of edema on different parts of the body, limbs.
Pain in the lower abdomen or lower back.
Decrease / increase in the volume of urine separated.

All these symptoms indicate problems with the kidneys, so when they appear, you should contact a qualified doctor as soon as possible and undergo an examination.

What to do with a low specific gravity of urine

If the specific gravity of urine is much lower than normal, first of all, it is necessary retake laboratory tests. Be sure to take a responsible attitude to the re-collection of biological fluid, on the eve of the diagnosis, do not drink too much liquid. If other indicators are normal, then most likely the person does not have any kidney disease.

If, in addition to low density, there are other deviations in laboratory tests, a comprehensive examination is mandatory. What it will include, the therapist or urologist must decide. Usually, patients are given referrals for an analysis according to Zimnitsky, which allows you to establish differences in urine density at different times of the day.

Specific gravity of urine during pregnancy

It is considered normal if the relative density of urine in the expectant mother is from 1.010 to 1.029.

The parameter reduction is provided by:

Excessive fluid intake.
Edema.
Hormonal surges.
Kidney pathologies (nephropathy)
Toxicosis.
Frequent urination.

If the criterion, on the contrary, is increased in a pregnant woman, the gynecologist may assume the presence of:

Diabetes.
Fluid deficiency, dehydration.
Inflammation of the kidneys.
Severe toxicosis / gestosis.

The expectant mother should not worry if the results of the analysis were unsatisfactory. The analysis should be retaken as soon as possible. Only if the re-diagnosis confirms the concerns that have arisen, the measures necessary to determine the cause of the condition will be carried out.

The specific gravity of urine is increased - causes and what to do

An increase in the specific gravity of urine in medicine is called hyperstenuria. Usually this problem develops against the background of a decrease in the amount of separated biological fluid.

It can be provoked by:

Severe vomiting, nausea.
Inadequate fluid intake, dehydration.
The introduction of a radiopaque substance into the patient's body on the eve of a laboratory study.
Proteinuria (presence of protein) in nephrotic syndrome.
Diabetes.
Taking large doses of antibiotics.
Inflammation of the organs of the genitourinary system.
Toxicosis during pregnancy.

Hyperstenuria is characterized by symptoms such as:

Discomfort in the abdomen.
Pain in the lower back.
The formation of edema for unknown reasons.
A sharp decrease in single portions of excreted urine.
Weakness, fatigue.

With hyperstenuria, as with hypostenuria, the patient should undergo a Zimnitsky test to understand if there are abnormalities in the work of the kidneys and get a complete picture of their functioning.

Diagnosis of each disease begins with the delivery of laboratory tests. One of the most informative indicators of the study is the relative density of urine. When the specific gravity of urine is significantly below normal, doctors insist on further diagnosis using modern examination methods. The reasons for this condition must be established, because many of them threaten the health and even life of a person.

What is low specific gravity of urine

Relative density is a parameter by which the functional activity of the kidneys is assessed by the concentration and dilution of urine. The amount of fluid circulating through the body is variable. Its volumes decrease and increase depending on many factors:

ambient temperature;
the amount of liquid in the diet;
time of day;
eating salty or spicy foods;
with profuse sweating during sports.

Normally functioning kidneys cope with the function of filtering and excretion, regardless of the volume of fluid - metabolic products should not accumulate in human blood. If there is a small amount of water in the body, then the secondary urine turns out to be concentrated, compacted, saturated dark in color. In medicine, this condition is called hyperstenuria, or increased relative density of urine.

With an increase in the amount of fluid in the body, an additional burden falls on the kidneys. The primary task is to filter the blood from the accumulated harmful decay products of substances:

Urea and its chemical compounds.
Chlorides, sulfates, ammonia.
Creatinine

At the next stage of urination, the kidneys remove a large amount of water from the body in order to reduce the load on the cardiovascular system and internal organs. The resulting urine is almost colorless, because the concentration of dry residue in it is extremely small. This condition is called hypostenuria, or low relative density of urine.

If hypostenuria is caused by natural causes (drinking liquids in the heat), then there is no cause for concern. But there are diseases in which a low specific gravity of urine is regularly detected according to the results of the study.

You can read more about the specific gravity of urine.

Using a urometer, the specific gravity of urine is determined

Why does the specific gravity of urine decrease?

Primary urine is formed in the process of blood filtration by single-layer capillary cells under a pressure of 70 mm Hg. Art. In the renal tubules, nutrients are reabsorbed from the primary urine back into the blood flowing through the capillaries. The process of reabsorption occurs due to the functional activity of the epithelial cells of the renal tubules. In just one day, about two liters of secondary urine is formed from 150 liters of primary urine.

The main reason for the decrease in the relative density of urine is a violation of the production of vasopressin, a peptide hormone of the hypothalamus. For example, in some types of diabetes insipidus, the daily volume of urine excreted by a person reaches 20 liters at a rate of 1.5 liters. This is due to the almost complete absence of vasopressin in the body.

Antidiuretic hormone (ADH) accumulates in the pituitary gland and then enters the bloodstream. Its main functions:

narrowing of the lumen of the veins and arteries;
fluid retention in the human body.

Antidiuretic hormone increases fluid reabsorption, increases the concentration of urine, reduces its volume. By regulating the amount of water in the human body, vasopressin increases the permeability of fluid in the tubules of the kidneys.

The content of solids in the urine is a variable value, which is directly dependent on the composition of the blood plasma. This process is regulated by nervous and humoral mechanisms. With an increase in salt content, the production of vasopressin increases, which enters the kidneys with blood and increases the reabsorption of fluid from the primary urine. The concentration of secondary urine increases, along with it, all harmful substances are removed from the body, and only a small amount of liquid.

If the blood contains a large amount of fluid, then the concentration of antidiuretic hormone decreases, as does reabsorption. Secondary urine consists of a small amount of solids dissolved in a large volume of water.

How is low urine specific gravity determined?

The fact that a person has a reduced relative density of urine is often detected when diagnosing diseases that are in no way related to the urinary system. The determination of the specific gravity occurs as a result of a general urinalysis, along with the content of leukocytes and products of protein metabolism. But it is difficult to overestimate the information content of the indicator - with its help, doctors detect severe pathologies that require urgent treatment.

As a rule, a low specific gravity of urine is determined during functional tests:

Folgart test.

Such measurements help to obtain more accurate relative density results and even approximately determine the cause of hypostenuria. For example, when the indicator drops to 0.01, we can talk about isosthenuria, which occurs when the kidney is wrinkled. Isosthenuria is diagnosed in a person whose kidneys have completely lost the ability to concentrate and remove urine from the body.

The main instrument in carrying out functional tests is the urometer.

The study is carried out in several stages:

The urine sample is placed in the cylinder. If a small amount of foam appears, then it is disposed of with filter paper.
With a little effort, the urometer is immersed in the urine. The device should not come into contact with the walls of the cylinder - this will distort the results of the study.
After the disappearance of the oscillations of the urometer, the relative density is measured along the border of the lower meniscus.

To obtain a more accurate result, it is important to take into account the ambient temperature, taking an average value of 15 ° C as a basis.

By the way, today you can successfully measure the specific gravity of urine at home using multi-indicator test strips. If a person has diabetes insipidus, frequent determination of urine density is required to monitor the progress of therapy. Test strips make the life of the patient much easier, because the state of health does not always allow him to leave the house.

Causes of Decreased Relative Density of Urine

The specific gravity of urine is lowered when the density level drops to 1.01. This condition signals a decrease in the functional activity of the kidneys. The ability to filter harmful substances is significantly reduced, which can lead to slagging of the body, the occurrence of numerous complications.
But such an indicator is sometimes taken as the norm. For example, in pregnant women, hypostenuria often develops with toxicosis. In this condition, women sometimes experience disturbances in the functioning of the gastrointestinal tract, which cause fluid retention in the body. Expectant mothers suffer from urination disorders - urine is excreted frequently, but in small portions.

A decrease in the relative density of urine in pregnant women also occurs for the following reasons:

Kidney disorders. When carrying a child, many factors arise, under the influence of which the ability of the kidney to function actively decreases. This is a growing uterus, squeezing the organs of the small pelvis. It also expands the circulatory system, which increases the load on the kidneys.
Change in hormonal background. Increased production of female sex hormones causes a certain imbalance of other biologically active substances.

Immediately after the baby is born, the first urine sample is taken from him to assess the work of the kidneys and general health. As a rule, the specific gravity of the urine of a newborn does not exceed 1.015-1.017. Such indicators persist during the first month of life, and then begin to increase with a change in diet. Hypostenuria in infants is considered normal and does not require medical intervention.

Read more about reducing the specific gravity of urine in children.

Hypostenuria is noted in healthy people who have consumed significant amounts of liquid or products with a diuretic effect (watermelon, melon). Adherents of a monotonous diet are diagnosed with a decrease in urine density - a lack of protein products in the diet is formed. The use of diuretics in the treatment of various diseases also leads to hypostenuria, but this condition is usually corrected by changing diuretic drugs or reducing their dosage. The concentration of solids in secondary urine decreases with the resorption of edema or increased sweating during colds.

It is extremely important to distinguish between the physiological and pathological causes of a decrease in the specific gravity of urine. Pathologies of the kidneys lead to violations of the filtration of chemical compounds, therefore, a decrease in the density of urine develops not due to the large amount of fluid consumed, but as a result of the resulting diseases of the urinary system.

If, during functional tests, a monotonous relative density of urine is recorded during the day, the doctor will definitely prescribe further studies.

Diseases in which the specific gravity of urine decreases

There are three main types of pathologies in which the production of vasopressin is reduced and fluid reabsorption does not occur. With each urination, a large volume of urine is released with a low concentration of urea and its salts. These diseases include:

involuntary polydipsia;
neurogenic diabetes insipidus;
nephrogenic diabetes insipidus.

When diagnosing low urine density, doctors suspect the development of these particular diseases, especially when the patient complains of the following symptoms:

The occurrence of edema of various localization.
Pain in the abdomen and lower back.
Urine became darker in color, blood impurities appeared in it.
Decreased volume of urine with each urination.
Often there is drowsiness, insomnia, weakness, apathy.

The addition of a bacterial infection of the bladder leads to an expansion of symptoms: pain during urination appears, the temperature rises, and disturbances in the functioning of the gastrointestinal tract occur.

Polydipsia causes decreased specific gravity of urine

Polydipsia

Polydipsia is a disease in which there is intense thirst. To satisfy it, a person drinks a huge amount of liquid, far exceeding the physiological need. The kidneys filter out the increased volumes of blood, resulting in unconcentrated urine.

Involuntary polydipsia is diagnosed in people whose mental state is extremely unstable. To determine the disease, it is usually enough to interview the patient and the results of the relative density of urine.

Neurogenic diabetes insipidus

The main symptoms of neurogenic diabetes insipidus are constant thirst and frequent urination. The disease develops with insufficient production of vasopressin by the hypothalamus. What factors can cause pathology:

head injury;
infectious diseases;
malignant and benign neoplasms;
consequences of surgical operations;
congenital pathologies.

The absence of antidiuretic hormone leads to fluid loss in the formation of highly dilute urine. A person seeks to make up for the loss by drinking large volumes of fluid, but the lack of vasopressin in the body leads to a vicious circle.

Violation of the hypothalamus leads to a decrease in the specific gravity of urine

Nephrogenic diabetes insipidus

The disease develops when the kidney fails to respond to vasopressin. The reason for this may be the use of certain medications, as well as:

Chronic renal failure.
Urolithiasis disease.
Sickle cell anemia.
Congenital pathologies of the kidneys.

If the cause of diabetes during the diagnosis was not established, then idiopathic diabetes insipidus is determined.

With a decrease in the specific gravity of urine, further careful examination is required. This means that there is a hidden pathology in the body, and it requires urgent medical or surgical treatment.

Today, in order to assess the state of human health and diagnose any ailment, it is necessary to conduct a series of laboratory tests. One of the simplest and most informative is urinalysis, according to its results, one can recognize not only the presence of diseases of the urinary system, but also other pathologies and abnormalities in a person.

When evaluating the test material, the relative density of urine (its specific gravity) is of no small importance. By this parameter, it is possible to determine how actively and fully the kidneys function, whether the processes of accumulation, filtration and excretion of urine occur correctly in the body.

What is this parameter for, what is the normal density of urine, and what pathologies can the level deviation from the normative values indicate. Let's take a closer look in this article.

What is the specific gravity of urine?

The specific gravity (relative density) of urine is a parameter that shows the accumulation of components dissolved in it: uric acid and urea, salts, etc., compared with the total amount of its excretion at a time. In other words, this indicator reflects the ability of the kidneys to carry out the concentration of urine and its dilution.

Many, seeing unfamiliar designations in the analysis form, want to know what they mean. The question often arises, what is sg in a urinalysis. The SG value is used to denote the density or specific gravity of the fluid in question. Therefore, in laboratory conditions, the parameter we are considering is often recorded as a urine test sg.

Today, it is not difficult to determine the density of urine. To do this, the laboratory uses a special device urometer (hydrometer), with divisions of 1.000-1.060. To determine the specific gravity in urine, the test material is placed in a specialized cylinder, the resulting foam is removed with filter paper (if necessary), then the specialist evaluates and fixes the position of the lower meniscus of the device and the scale that advises it.

This will be the final figure for the specific gravity of urine as a result of the analysis.

Urine density norm

In a healthy adult, the relative specific gravity of urine (density) can range from 1.018 to 1.025. In children under 12 years of age, the specific gravity of urine is considered normal if it is in the range of 1.012-1.020.

The specific gravity of urine is the norm for women and men does not differ, however, during pregnancy for a woman, an indicator in the range of 1.003-1.035 is considered normal. Moreover, expectant mothers often have a low specific gravity of urine, especially in the first half of pregnancy, when many show toxicosis, vomiting, and, as a result, dehydration.

It should be noted that the normal density of urine in all people changes markedly during the day. This is due to the fact that new metabolic products are formed in the body, the volume of fluid consumed and excreted may change, moisture loss also occurs during sweating and even breathing.

But, one way or another, the result obtained must be within the established limits of the normal density of urine.

Cases when a significantly reduced or increased density of urine is recorded in a patient are considered as violations that require detailed consideration.

The relative density of urine is increased, what does this mean?

When the specific gravity of urine exceeds the maximum allowable value for healthy people (1.025 for adults and 1.020 for children), experts speak of a violation of renal concentration. The medical term hyperstenuria is often used for this condition.

Hyperstenuria is an increase in sg density of urine to a value of 1.030 or more. In this condition, as a rule, a significant concentration of various elements is observed in the urine, including salts, proteins and glucose.

Reasons for increased urine density:

Often, it is almost impossible to detect by the appearance of the patient that the specific gravity in the urine is increased, except in cases where severe edema is formed throughout the body due to cardiovascular insufficiency. Basically, it is possible to establish the deviation of the indicator only after conducting a clinical study of urine (namely, urine analysis of specific gravity).

Low urine density

A decrease in the relative specific gravity of urine is characterized by the release of a large amount of water.

Hypostenuria is a marked decrease in the specific gravity of urine to a value of 1.010 and below, often due to a malfunction of the renal tubules, which concentrate the glomerular filtrate.

This condition can occur in children of the 1st year of life, and it does not indicate the ill health of organs or systems in babies.

In adults, the low specific gravity of urine causes the following pathological factors:

Renal failure in a chronic cycle;
"Insipid" diabetes (central, nephrogenic, idiopathic), when urine sg can be less than 1.005 g / l;
Chronic nephritis (inflammation of the kidneys) or pyelonephritis (bacterial disease, inflammation of the renal pelvis, parenchyma, calyces);
renal cysts;
Violation of the full-fledged work of the hypothalamus and pituitary gland, resulting in a lack of a special hormone vasopressin, which is responsible for the absorption of water in the renal tubules. This disorder leads to the production of too dilute urine with a reduced density;
Incorrect intake of diuretics;
Excessively abundant drinking regimen, passion for the consumption of all kinds of drinks throughout the day;
Prolonged starvation, nutritional dystrophy, lack of nutrients, adherence to a diet "without proteins" can lead to a significant change in the density of urine to a smaller side.

It happens that a decrease in the considered indicator of urine occurs if the patient abuses alcoholic beverages, especially for men who like to lean too often on beer. It should be noted that as soon as a person stops being addicted to alcohol, or normalizes his diet, the indicator soon returns to normal.

Hyperstenuria and hypostenuria, what it is, is more or less clear. But, how to detect pathological changes in your body that provoked an increase / decrease in the density of urine?

Additional Research

It should be noted that by a single change in the indicator, one can only conditionally suspect something was wrong in the concentration of the renal ability. To make the assessment more reliable, the patient is offered to retake the urine test sg to the norm, or to conduct a diagnostic urine test according to Zimnitsky, when daily fluctuations in density are assessed. A person during the day approximately collects 8 servings of urine at regular intervals (~ every 3 hours). Then, using the device, the difference between daytime and nighttime diuresis is determined. There should be a discrepancy of approximately 30% at different times of the day.

Also, several more types of functional tests can be used to confirm fluctuations when the specific gravity of urine is increased / decreased. For example, a test with a dry diet (or it is called a concentration test). The essence of the study is to change the patient's diet. All foods with a large amount of liquid (soups, compotes, teas, etc.) are excluded from the menu for a day, and the use of the liquid itself should be reduced to a few sips a day.

Such a routine is quite difficult for many patients, but with the help of this method it will be easier for physicians to assess the physiological parameters and the relative density of urine. If, after a day, the indicator remains underestimated (within 1.015-1.017 g / l), it means that the kidneys still cannot cope with their ability to properly concentrate urine before excreting it. If the result shows that after such a "dry" method of research, the density of the urine is increased or close to normal, then the kidneys are functioning as they should.

Sometimes, I use a test with a water load, which also allows you to evaluate the concentration ability of the kidneys.

What to do in case of deviations from the norm?

If renal disorders are detected, it is advisable to refer the patient to a hospital for further examination and treatment. The patient should at least be closely monitored by a specialist nephrologist (urologist, internist or endocrinologist).

Patients with diabetes should, like no one else, be responsible for any changes in urine density and follow all the recommendations and advice of a doctor, since diabetes can lead to the rapid development of renal pathologies and make it difficult to further cure them.

There is no fundamental treatment strategy for deviations in the specific gravity. It all depends on the identification of the cause and neglect of the condition of the diseased organ. Subsequently, on an individual basis, the doctor prescribes drugs and a set of therapeutic measures that will help to influence and eliminate the primary source of the disease.

In renal failure, a prerequisite for treatment is a sparing diet and a healthy lifestyle. Otherwise, a successful cure may take a very long time. The patient is advised to exclude spicy, smoked foods, pickles and all kinds of culinary “spices” from the menu. About the rejection of alcohol and tobacco, it should not even be mentioned, it goes without saying. An important role is played by the restoration or normalization of the water balance (or, on the contrary, the restriction of water consumption).

If hyperstenuria / hypostenuria is observed in a patient for a long time (a chronically recurring phenomenon), the patient is registered and they are talking about a systemic examination every quarter (3 months).

If a person cares about his health, he probably regularly visits a doctor and undergoes the necessary laboratory tests, incl. checks the rate of specific gravity of urine. After all, early diagnosis of kidney disorders increases the likelihood of a speedy cure and prevents the risk of unpleasant symptoms and all kinds of complications.

Take good care of your health!

Any disease detected at an early stage of the course is much easier to treat than a rapidly progressing pathology. This pattern is especially relevant for young children, who get sick more often and more severely than adults. The appearance of the first alarming symptoms should not be ignored - this will avoid serious complications. Laboratory studies of the specific gravity of urine in children help to detect a disease that is just beginning to emerge in the baby's body. Not always a decrease or increase in the indicator indicates the presence of a pathology - for a certain age this is the norm that does not require treatment.

What does the specific gravity of urine in a child show?

Experienced parents have long learned to decipher the mysterious numbers and terms printed on the form with the results of the tests. No wonder, because every visit to the hospital ends with the delivery of blood and urine by the child. But most dads and moms pay attention to the content of leukocytes and protein breakdown products, and not to the specific gravity of urine. But in vain - the relative density of urine signals the beginning of negative processes in various systems of life.

This parameter assesses the ability of the kidney to concentrate and dilute urine for optimal excretion of all harmful substances. In order for toxic compounds to quickly leave the baby's body, the kidneys filter the blood, regardless of the volume of fluid circulating in the body. If there is little water in the blood, then concentrated secondary urine is formed. It contains a lot:

urea and its compounds;
chlorides and sulfates;
creatine.

When pathologies occur, dissolved ammonia and pathogenic microorganisms appear in the urine, which do not occur in normal health.

You can visually determine that the child's urine is thickened: it becomes darker in color, and its separated volume is relatively small.

With a large volume of fluid in children, highly dilute urine with a small amount of dissolved solids is formed. The kidneys experience a double load: they filter out harmful substances and remove a lot of fluid. Such urine is completely transparent in appearance, odorless and colorless.

The relative density of urine allows you to detect pathologies in the early stages

How is the determination of the relative density of urine

When the test results of children strongly deviate from the norm, parents have reason to worry. First of all, you should make sure that there is no error due to incorrect collection of urine. Only morning urine, which is placed in a clean, dry container, is suitable for analysis. You can purchase a special sterile container at the pharmacy - it does not need to be washed and dried. Baby urinals are great for newborns:

for boys;
for girls;
universal.

The child must be washed with warm water using hypoallergenic soap. Now the most difficult thing remains - to catch the moment of urination. Almost all parents know the special signs that precede this moment: babies tense up, frown or wince. An average portion of urine is best for determining specific gravity.

It is not necessary to collect urine even in a dry and clean pot, the required sterility is violated, and this will lead to erroneous test results. Sometimes moms and dads just squeeze a diaper or diaper into the container. Such urine can not be taken to the laboratory - the parameters obtained will have a lot of errors.

The relative density of urine is determined using a special urometer device. The child's urine is placed in a cylinder, and the resulting foam is removed with a piece of filter paper. Carefully, trying not to touch the walls, the urometer plunges into the cylinder. Lab technicians make little effort to optimally position the device. After the oscillations subside, the readings of the urometer are noted on the lower scale.

The calculation takes into account the ambient temperature and makes adjustments. In hot weather, babies drink a lot of fluids, so the urine will be more dilute. Also, children are more mobile than adults, they have a fast metabolism and high vascular permeability. All these factors affect the measurement results.

It is convenient to collect urine for determination of specific gravity in a special container

What indicators of the specific gravity of urine are considered the norm

Normal indicators of the relative density of urine in an adult are 1.01-1.025. Deviation from these parameters even by one division of the urometer scale requires careful further examination. Having ruled out the possibility of a decrease or increase in the specific gravity of urine under the influence of physiological factors (excessive fluid intake), doctors begin to look for the cause of the anomaly.

Immediately after the birth of the child, the first urine sample in his life is taken.

Normal relative density for this age is 1.005-1.017. The newborn has not yet debugged the nutrition system, the water-salt balance has not normalized, and such parameters persist throughout the first month of the baby's life. As the specific gravity increases, the kidneys begin to function actively. The following parameters of urine density are considered within the normal range:

From one to four years: 1.007-1.016.
From five to ten years: 1,011-1,021.
From eleven to fifteen years old: 1.013-1.024.

A low specific gravity of urine is called hypostenuria. The kidneys do not cope with their function of concentrating urine, and it is excreted in a large volume, but with a reduced content of salts and urea.

The increased relative density of urine is called hyperstenuria. The urine excreted during urination is insufficiently diluted, oversaturated with metabolic products. When prescribing further examinations, doctors are also guided by other indicators of biochemical urine tests, for example, the content of leukocytes. Their increased concentration indicates the presence of an inflammatory process in the child's body. Such an infectious focus can significantly affect the parameters of the specific gravity.

The density of urine is not a constant value - it varies throughout the day and depends on the following factors:

intake of spicy, salty, fatty foods;
changes in drinking regimen;
profuse sweat.

Morning urine is the most concentrated, because at night a person does not drink liquid, he does not experience increased sweating. Functional tests are the most informative in detecting pathologies. The child takes urine several times a day at regular intervals. Doctors compare the readings obtained with the help of a urometer and select further diagnostics. For example, if the relative density of urine has not changed in a day, then pyelonephritis can be suspected in the baby.

Diarrhea and vomiting are causes of decreased relative gravity of urine in children

The specific gravity of urine in a child is higher than normal

An increase in the relative density of urine, or hyperstenuria, is often diagnosed in babies who drink little water. Their urine is always too concentrated, its color varies from dark yellow to dark brown. Especially often this happens in the hot season, when there is a natural loss of moisture through increased sweating.

Children get sick much more often than adults. Many of the diseases are accompanied by disorders of the gastrointestinal tract: vomiting and diarrhea. In this case, there is a large loss of fluid, which contributes to an increase in the specific gravity of urine. The indicators also increase in the following cases:

In children with cardiovascular pathologies, fluid accumulates in the body due to the development of swelling.
In diabetes mellitus, the specific gravity of urine is significantly higher than normal. The mass of the dry residue increases, as it contains a lot of sugar.
If a child has infectious diseases, then the proportion increases due to pathogenic microorganisms.

The relative density is always increased in the presence of pathologies of the urinary system. Congenital and acquired diseases of the kidneys, urinary tract and bladder are accompanied by urination disorders and urine stagnation. These symptoms are similar to those of hyperstenuria:

excretion of a small amount of urine with each urination;
dark color of urine;
unpleasant smell of urine;
the appearance of edema of various localization;
increased weakness, fatigue, drowsiness, apathy;
stomach ache.

A high urine density is recorded during antibiotic treatment, as well as with intestinal obstruction. Blunt abdominal trauma can cause an increase in specific gravity.

The specific gravity of urine is determined using a urometer

The specific gravity of urine in a child is below normal

The low relative density of urine in a child can be due to both physiological and pathological causes. Natural factors include:

After illnesses, especially of infectious origin, doctors recommend that children drink plenty of water to restore the water-salt balance.
For some diseases of the urinary or cardiovascular system, the child is prescribed diuretics. Under their influence, the volume of urine excreted increases, but the amount of salts dissolved in it is very small.
After eating some foods, the child may become very thirsty and drink a lot of fluids, which reduces the density of urine.
The volume of urine is increased, and the number of urination increases when eating watermelons and melons.

Hypostenuria also occurs for pathological reasons. The kidneys lose their ability to thicken urine when removing harmful substances from the child's body. Therefore, getting rid of the body from toxic compounds occurs when large volumes of urine are excreted. The kidneys are under increased strain, filtering a significant amount of blood. This condition requires accurate diagnosis to determine the cause of the pathology.

The specific gravity of the urine of a child will always be reduced in such diseases:

Polydipsia. With this disease, a person experiences constant thirst and drinks water in large quantities. Sometimes this condition is diagnosed in mentally unstable people; children rarely fall into this category. Pathology often does not need a thorough diagnosis, a description of the symptoms by the parents is enough.
Neurogenic diabetes insipidus. The synthesis of antidiuretic hormone by the pituitary gland is disrupted, and prolonged dehydration develops.
Nephrogenic diabetes insipidus. The cells of the distal nephron tubule lose their ability to respond to antidiuretic hormone.

You can read more about the causes of low specific gravity of urine.

All these pathologies require immediate treatment, as they provoke serious complications.

Regular laboratory tests help to identify diseases in the early stages, and immediately begin therapy. Urine specific gravity is an important part of the initial diagnosis of pathologies.

Urinalysis (general) evaluates the physical and chemical properties of urine, determines the composition of the sediment. On this page: description of the urine test, norms, interpretation of the results.

Physical parameters:

urine color,
transparency,
relative density,
urine pH (urine reaction).

Chemical indicators (presence or absence):

protein,
glucose,
urobilinogen,
bilirubin,
ketone bodies,
nitrites.

Microscopic examination of the sediment may reveal:

epithelium (squamous, transitional, renal),
leukocytes,
erythrocytes,
cylinders,
slime.

In addition, salts, crystals of cholesterol, lecithin, tyrosine, hematodin, hemosiderin, fatty acids, neutral fat are found in the sediment; bacteria, Trichomonas, spermatozoa, yeast.

Indications for performing a urinalysis (general)

Diseases of the kidneys and urinary tract.

Screening examination when visiting specialists of various profiles.

Study preparation

On the eve exclude vegetables that change the color of urine (beets), drugs (diuretics, aspirin).

In the morning, it is necessary to perform the toilet of the external genitalia and collect urine in a pre-prepared sterile container. Women are not recommended to collect urine for analysis during menstruation. Urine must be delivered to the laboratory of a polyclinic or medical center in the morning of the same day, since after a few hours the physical properties of urine change and sediment elements are destroyed, the analysis becomes uninformative.

Research material

Urine (morning portion), not less than 10 ml.

Deciphering the results

Physical properties:

1. Urine color

Norm: straw yellow.

A change in the color of urine may be due to food, medicines, or be a sign of some diseases.

urine color	Possible cause of discoloration
Pale yellow, light	Diabetes insipidus, taking diuretics, decreased concentration function of the kidneys, excess water content in the body
Dark yellow	Dehydration, swelling, vomiting and diarrhea, burns. Edema in heart failure
beer color	Parenchymal jaundice in viral hepatitis
Orange, yellow-orange	Furagin, Furomag, B vitamins
	Kidney infarction, renal colic
The color of "meat slops", red-brown	Acute glomerulonephritis
	Beets, blueberries, aspirin
Red-brown	Phenol poisoning. Taking sulfonamides, metronidazole, drugs based on bearberry
greenish yellow color	Obstructive jaundice (due to blockage of the bile ducts) with cancer of the head of the pancreas or in the presence of stones in the gallbladder (calculous cholecystitis)
White milk	Fat droplets, pus, or inorganic phosphorus
Black color	Melanoma, alkaptonuria (hereditary disease), Marchiafava-Michelli disease (paroxysmal nocturnal hemoglobinuria)

2. Clarity of urine

Norm: transparent.

Turbid urine may be due to mucus and epithelium. When urine is stored at a low temperature, its salts can precipitate and cause turbidity. Long-term storage of the material for research leads to the multiplication of bacteria in it and clouding of the urine.

3. Specific gravity or relative density

Norm for children over 12 years old and adults: 1010 - 1022 g/l.

The specific gravity of urine is affected by the amount of excreted fluid, organic compounds (salts, urea), electrolytes - chlorine, sodium and potassium. The more water is excreted from the body, the more "diluted" the urine will be and the lower its relative density or specific gravity.

Decreased (hyposthenuria): less than 1010 g/l.

It is observed in renal failure, when the concentration ability of the kidneys is impaired.
diabetes insipidus;
Chronic renal failure;
Drinking large amounts of water, taking diuretics.

Increase (hyperstenuria): more than 1030 g/l.

The presence of protein or glucose in the urine. Occurs at:

diabetes mellitus, poorly responding to ongoing therapy;
the appearance of protein in the urine with glomerulonephritis;
intravenous administration of radiopaque substances, dextran or mannitol solutions;
insufficient fluid intake;
toxicosis of pregnant women.

4. Urine reaction (urine pH)

Norm: 5.5-7.0, acidic or slightly acidic.

The nature of nutrition and the presence of diseases in the body affect the reaction of urine. If a person prefers meat food, then the urine reaction is acidic. With the use of fruits, vegetables and dairy products, the reaction shifts to the alkaline side. In addition to dietary habits, the following reasons are possible.

Alkaline reaction, pH > 7, increase in pH:

respiratory or metabolic alkalosis,
renal tubular acidosis (type I and II),
hyperfunction of the parathyroid gland,
hyperkalemia,
prolonged vomiting,
tumors of the urinary system,
urinary tract and kidney infections caused by bacteria that break down urea,
taking adrenaline or nicotinamide (vitamin PP).

Acidic, pH around 4, lowering pH:

respiratory or metabolic acidosis,
hypokalemia,
starvation,
dehydration,
prolonged fever,
diabetes,
tuberculosis,
intake of vitamin C (ascorbic acid), methionine, corticotropin.

Chemical properties:

1. Protein in the urine

Norm: missing.

The appearance of protein in the urine is a signal of trouble in the work of the kidneys. An exception is physiological proteinuria (protein in the urine), which is observed with severe physical exertion, strong emotional experience or hypothermia. The permissible protein content is up to 0.033 g / l, it is not determined by the usual reagents for performing a general urinalysis.

Boost: more than 0.033 g/l.

Possible reasons:

kidney damage in diabetes mellitus (diabetic nephropathy),
nephrotic syndrome,
glomerulonephritis,
myeloma,
urinary tract infections: urethritis, cystitis,
malignant neoplasms of the genitourinary system.

2. Glucose in the urine

Norm: missing.

During filtration in the renal tubules, glucose in healthy people is completely reabsorbed. Therefore, it is not detected or occurs in minimal quantities - up to 0.8 mmol / l.

Boost: presence in the analysis. If glucose appears in the urine, there are two reasons for this:

2. The renal tubules are affected, so there is no reabsorption of glucose. Occurs in case of poisoning with strychnine, morphine, phosphorus; tubulointerstitial lesions of the kidneys.

3. Bilirubin in urine

Norm: missing.

Biliribun appears in the urine when its concentration in the liver significantly exceeds normal values. This occurs when the liver parenchyma is damaged (viral hepatitis, cirrhosis of the liver) or with mechanical blockage of the bile duct and impaired bile outflow (mechanical jaundice, metastases of tumors of other organs in the liver).

4. Urobilinogen in urine

Norm: missing.

Urobilinogen is formed from bilirubin, which is the result of the breakdown of hemoglobin.

Boost: more than 10 µmol/day.

A) Increased breakdown of hemoglobin (hemolytic anemia, transfusion of incompatible blood, resorption of large hematomas, pernicious anemia).

B) Increased formation of urobilinogen in the intestine (intestinal obstruction, enterocolitis, ileitis.

C) An increase in the level of urobilinogen in the blood in liver diseases (chronic hepatitis and cirrhosis of the liver) or toxic damage (alcohol, bacterial toxins).

5. Ketone bodies

Norm: missing.

Ketone bodies include acetone and two acids - acetoacetic and beta-hydroxybutyric. They are formed during the increased destruction of fatty acids in the body. Their determination is important for monitoring patients with diabetes mellitus. If ketone bodies are found in the urine, then insulin therapy is chosen incorrectly. Ketoacidosis is accompanied by an increase in blood glucose, fluid loss, and electrolyte imbalance. It can end in hyperglycemic coma.

Conditions accompanied by the appearance of ketone bodies in the urine:

decompensated diabetes mellitus,
hyperglycemic cerebral coma,
severe fever,
prolonged fasting,
eclampsia in pregnant women
isopropanolol poisoning,
alcohol intoxication.

6. Nitrites in urine

Norm: missing.

A healthy person does not have nitrites in the urine. They are formed under the influence of bacteria from nitrates in the bladder if urine is in it for more than 4 hours. If nitrites appear in the urine, this is a sign of a urinary tract infection. More often than others, asymptomatic urinary tract infections are observed in women, in the elderly over 70 years of age, in patients with diabetes mellitus or gout, with prostate adenoma.

7. Hemoglobin in urine

Norm: missing.

When performing the analysis, it is almost impossible to distinguish between myoglobin and hemoglobin. Therefore, the laboratory assistant often describes the appearance of myoglobin in the urine as "hemoglobin in the urine." Both proteins should not appear in the urine. The presence of hemoglobin indicates:

severe hemolytic anemia,
sepsis
burns
poisoning with poisonous mushrooms, phenol, sulfonamides.

Myoglobin appears when:

rhabdomyolysis,

myocardial infarction.

Microscopy of sediment in urinalysis

To obtain a precipitate, a 10 ml tube is placed in a centrifuge. As a result, the sediment may include cells, crystals, and cylinders.

1. Red blood cells in the urine

Norm: up to 2 in sight

red blood cells are blood cells. Normally, up to 2 erythrocytes per 1 µl of urine enter the urine. This amount does not change its color. The appearance of a large number of red blood cells (hematuria, blood in the urine) indicates bleeding in any part of the urinary system. In this case, menstruation in women should be excluded.

Boost: more than 2 in sight.

stones in the kidneys or ureters,
glomerulonephritis,
pyelonephritis,
tumor of the genitourinary system,
kidney injury,
hemorrhagic diathesis,
systemic lupus erythematosus,
incorrect doses of anticoagulants.

2. White blood cells in the urine

Norm:

0-3 in the field of view in men,
0-5 in the field of view in women.

Leukocytes indicate the presence of inflammation in the kidneys or in the underlying sections. With a pronounced inflammatory process, a large number of leukocytes gives the urine a whitish tint (pyuria, pus in the urine). Sometimes leukocytes are the result of improperly collected urine: they penetrate from the vagina or from the mucous membranes of the external urethra with poor-quality hygienic toilets.

An increase in the number of leukocytes is a sign of an inflammatory process:

pyelonephritis acute and chronic,
glomerulonephritis,
tubulointerstitial nephritis,
stones in the ureter.

3. Epithelium in the urine

Norm:

squamous epithelium - in women, single cells in the field of view,
in men, single cells in the preparation.

The epithelium in the urine may be squamous, transitional, or renal. In healthy people, several squamous epithelial cells are present in the analysis. An increase in their number indicates a urinary tract infection.

Transitional epithelium appears with cystitis, pyelonephritis.

The renal epithelium is a sign of kidney tissue damage (glomerulonephritis, pyelonephritis, tubular necrosis, poisoning with heavy metal salts, bismuth preparations).

4. Cylinders in the urine

Norm: hyaline casts - single, no other casts

Cylinders are formed from protein and various cells, they may contain bilirubin, hemoglobin, pigments. These components form "casts" of a cylindrical shape from the walls of the renal tubules. There are hyaline, granular, waxy, erythrocyte cylinders.

Hyaline casts are formed from a special protein that is produced by the cells of the renal epithelium (Tamm-Horsfall protein). They are also found in healthy people, but the appearance of a large number of hyaline casts in several repeated analyzes indicates:

glomerulonephritis, acute or chronic,
pyelonephritis,
kidney tuberculosis,
kidney tumor,
congestive heart failure,

Granular casts are the result of the destruction of the epithelial cells of the renal tubules. If they are found at normal body temperature (no fever), then the following should be suspected:

glomerulonephritis,
pyelonephritis,
lead poisoning,
acute viral infection.

Waxy casts are a combination of hyaline and granular casts that coalesce in broad tubules. Their appearance is a sign of chronic kidney disease.

Amyloidosis of the kidneys
chronic renal failure,
nephrotic syndrome.

Erythrocyte casts are an association of hyaline casts with erythrocytes (blood cells). Their appearance indicates that the source of bleeding, the consequence of which is hematuria, is in the kidneys.

Acute glomerulonephritis;
thrombosis of the renal veins;
kidney infarction.

Leukocyte casts are a combination of hyaline casts with leukocytes. Characteristic of lupus nephritis with systemic lupus erythematosus, pyelonephritis.

Epithelial casts are extremely rare, found in acute diffuse glomerulonephritis, with rejection of a transplanted kidney.

5. Bacteria in the urine

Norm: missing.

Bacteria can be detected in the urine before the start of taking antibacterial agents and on the first day after the start of treatment. Their detection indicates the presence of an infectious process - pyelonephritis, cystitis, urethritis. For research it is necessary to collect a morning portion of urine.

6. Yeast

Norm: missing.

The appearance of yeast fungi of the genus Candida in the urine is a sign of candidiasis that has arisen with improperly selected antibacterial treatment.

7. Inorganic urine sediment, salts and crystals

Norm: missing.

Various salts are dissolved in the urine, which can precipitate or form crystals when the temperature drops or the pH of the urine changes. If a large amount of salt is found in the urine, the risk of kidney stones (risk of urolithiasis) increases.

Uric acid and urates are found in acidic urine (exercise, preference for meat in the diet, fever), gout, chronic renal failure, dehydration with vomiting and diarrhea.

Hippuric acid crystals are a sign of diabetes, liver disease, or eating blueberries, lingonberries.

Amorphous phosphates appear with alkaline urine in healthy people, after vomiting or gastric lavage, with cystitis.

Oxalates are found in the urine when eating foods containing oxalic acid (sorrel, spinach, rhubarb, asparagus), diabetes, pyelonephritis.

Tyrosine and leucine in the urine are a sign of phosphorus poisoning, severe metabolic disorders or pernicious anemia, leukemia.

Cystine is found in cystinosis, a congenital disorder of cystine metabolism.

Fatty acids and fat enter the urine with excessive intake of fish oil from food or with degenerative changes in the epithelium of the kidney tubules.

Cholesterol in the urine indicates fatty degeneration of the liver, echinococcosis, chyluria, or cystitis.

Bilirubin appears in the urine with hepatitis, liver cancer or phosphorus poisoning.

Hematoidin is present in the urine during chronic bleeding in the urinary system, especially if there is blood stasis.

8. Mucus in the urine

Norm: insignificant amount.

The epithelium of the mucous membranes secretes mucus, which in a healthy body is noted in small quantities. A lot of mucus happens during inflammatory processes in the organs of the urinary system.

Symptom Map

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