Urinalysis according to Zimnitsky - carrying out the procedure and deciphering the results

Zimnitsky's test is a basic urine test that provides information about the condition of the kidneys. During the study, the volume and density of urine excreted by the body during the day is checked, and material is collected according to a special scheme. Diagnostics are prescribed when there is a suspicion of the development of renal failure and other kidney diseases, including inflammatory ones.

What is the Zimnitsky test?

Urine examination according to Zimnitsky makes it possible to assess the functional ability of the kidneys for osmotic dilution and concentration. The technique is relatively simple and accessible. Urine collection is carried out for 1 day with an interval of three hours. The resulting eight portions are evaluated individually and jointly.

The analysis can be prescribed on an outpatient basis or performed in a hospital setting. It is most often used by therapists, urologists, nephrologists and cardiologists. Sample decoding according to Zimnitsky does not require unique equipment, so it can be performed in almost any large laboratory.

Relative density of urine

Hyposthenuria

– low urine density (in none of the portions does the urine density exceed 1.012–1.013 g/ml) indicates a violation of the concentrating ability of the kidneys, the cause may be:

chronic renal failure;
heart failure;
diabetes insipidus.

Hypoisosthenuria

– the density of urine in each portion of Zimnitsky’s test does not exceed 1.009 g/ml and practically does not change throughout the day. The cause may be severe kidney failure.

Hyperisosthenuria

– constantly high specific gravity of urine, the cause may be:

diabetes;
acute or chronic glomerulonephritis;
toxicosis of pregnant women;
nephrotic syndrome.

Indications for prescribing the Zimnitsky test

This study is prescribed in the following cases:

for the primary diagnosis of diseases of the urinary tract, cardiovascular system, pancreas and other organs;
when the color of the urine changes (cloudy, too concentrated or clear);
for control of chronic diseases (glomerulonephritis, pyelonephritis, diabetes mellitus and diabetes insipidus, renal, liver and heart failure, hypertension, etc.);
if you complain of aching pain in the lumbar region, difficulty urinating, swelling, etc.;
if the general urinalysis has pronounced deviations.

The study may also be recommended for patients taking diuretics for a long time, receiving parenteral nutrition, who have recently undergone an X-ray examination of the urinary system with contrast, and in some other cases. If urine collection and analysis are performed correctly, the doctor receives complete information about the functioning of the kidneys, the state of their filtration and excretory functions.

Interpretation of the result

At the medical office, you can get personal advice from a doctor from the “Doctor Q” service on interpreting the results of the study during your appointment or by phone.

It must be remembered that interpretation of the results of a urine test according to Zimnitsky should only be carried out by a doctor, since the results of laboratory tests are not the only criterion for making a diagnosis and prescribing appropriate treatment. They should be considered in conjunction with medical history and the results of other possible examinations, including instrumental diagnostic methods.

An adult normally excretes approximately 67–75% of the liquid he drinks during the day. Daytime diuresis should exceed nighttime and amount to 2/3–3/4 of the total amount of daily urine. The relative density during the day ranges from 1.005 to 1.025 g/ml.

If night diuresis predominates over daytime diuresis, then this indicates a decrease in the concentrating ability of the kidneys. Nocturnal predominance of diuresis is often found in diabetes insipidus and heart failure.

An excess of urine density above 1.025 g/ml is observed in cases of dehydration, pyelonephritis, and uric acid diathesis in children.

A decrease in urine density below 1.005 g/ml indicates a decrease in the concentration function of the kidneys and occurs in renal failure, chronic glomerulonephritis and pyelonephritis, diabetes insipidus and diabetes mellitus, hyperaldosteronism, while taking diuretics, severe potassium deficiency, excess calcium,

To confirm the resulting pathological abnormalities, the doctor may prescribe stress tests to the patient to dilute and concentrate urine.

Preparation for the procedure

The Zimnitsky test does not require special preparation. On the eve of the study, the medical professional explains in detail to the patient how to properly collect biological material. The analysis is carried out against the background of the abolition of all diuretics. Drinking and eating regimen remains unchanged.

The patient is given 8 sterile containers for urine. On each one they write the patient’s name, portion number and collection time (from 6 to 9 o’clock, from 9 to 12, and so on until six in the morning of the next day). If the test is carried out in a hospital, indicate the ward and department in which the patient is located. Additionally, 1-2 containers are given in case there is too much urine for the person to completely empty the bladder into the reservoirs for examination.

The patient is recommended to use an alarm clock, which will warn him every 3 hours about the deadline for collecting the next portion. A notepad is required. During the day, a person writes down the amount of liquid he drinks. This will allow laboratory physicians to assess overall urine output.

Preparing the patient for a general urinalysis and urine analysis according to Zimnichsky

How to properly prepare and take a urine test

Preparing for the test

The composition of urine is influenced by many factors - our food and drink, stress, physical activity, taking medications and dietary supplements. To ensure that the examination results are not distorted by random factors, you should prepare for a general urine test.

1. The day before collecting biomaterial, you should avoid foods that can change the color of urine (for example, brightly colored fruits, vegetables and dishes made from them, smoked meats, sweets and marinades).
2. You should not drink alcohol, take vitamins, dietary supplements, or diuretics (including coffee).
3. If you are taking any medications, tell the doctor who referred you for the test.
4. Try to avoid serious physical activity, baths and saunas.
5. Menstruation, an infectious disease with an increase in temperature, or a significant increase in blood pressure are a good reason to reschedule the tests; the results will still be distorted.
6. It is not recommended to take a urine test within 5–7 days after cystoscopy.

General urine analysis

Samples must not be contaminated with foreign matter. Therefore, you must follow all the rules for collecting material.

— For a general urine test, morning urine is used, which is collected in the bladder during the night.
— Before collecting the material, you should take a shower—failure to comply with this rule may result in the detection of an increased number of red and white blood cells in the urine.
— Dishes for collecting samples must be sterile, without traces of cleaning agents and disinfectants. Nowadays, disposable containers are mainly used for these purposes.
— To prevent bacteria from the external genitalia from getting into the sample, you need to release a small amount of urine into the toilet, and then, without stopping urination, place a container and collect 100–150 ml. The container should not touch the skin.
— Urine collected for general analysis can be stored for no more than 1.5–2 hours, and always in a cool place, at a temperature of 5–18? C. Urine that has been stored at room temperature is not suitable for analysis.
— Sterile urine bags are used to collect urine from newborns. Otherwise, the rules for children are the same as for adults. Urine is collected in the morning; before collecting the material, the baby must be thoroughly washed and dried with a clean, dry towel.
Rules for the collection and storage of urine according to Zimnitsky
The patient must collect biological fluid throughout the day. This will have to be done even at night. To collect urine you will need 8 clean and dry containers. On them the patient indicates his last name and initials, the serial number of the portion and the time interval.
You need to collect urine for analysis according to Zimnitsky as follows. During the first bowel movement after waking up between 06:00 and 09:00, no biological fluid is taken.
Then, from 09:00, 8 portions of urine are collected:
from 09:00 to 12:00 – portion No. 1;
from 12:00 to 15:00 – portion No. 2;
from 15:00 to 18:00 – portion No. 3;
from 18:00 to 21:00 – portion No. 4;
from 21:00 to 24:00 – portion No. 5;
from 24:00 to 03:00 – portion No. 6;
from 03:00 to 06:00 – portion No. 7;
from 06:00 to 09:00 – portion No. 8.
During these periods of time, a person may experience several urges to urinate. All liquid is collected . This needs to be taken into account. You cannot pour anything into the toilet. If a particular jar is overfilled, then an additional container is taken to collect it. It indicates the corresponding time interval. It can also happen when a person does not want to go to the toilet at a certain time. In this case, the jar is left empty and sent as is.
The volume of urine in each sample is measured and recorded. After the last portion is ready, all jars, including empty ones, are sent to the laboratory.
Another important point is that the patient needs to measure the amount of fluid consumed. Not only the water or juice you drink is taken into account. The liquid contained in the food is also taken into account. The doctor needs this information to correctly interpret the results.
Urine for analysis according to Zimnitsky should be stored in closed containers in a cool place. You can use a refrigerator. The storage temperature should not fall below zero.

Research stages

The analysis is carried out within 24 hours. At 6 am the patient wakes up to an alarm clock (in the hospital a nurse wakes him up). Weight is measured. The patient then urinates in the toilet. All subsequent portions of urine are collected in prepared sterile containers, strictly every 3 hours. If the patient cannot go to the toilet during a certain period of time, a mark is made on the corresponding container: 0 ml. When using an additional container, an inscription is left on it - for example, Petrov V.V., Zimnitsky sample, portion V, 18-21, 150 ml.

The tanks filled with urine are immediately tightly closed and placed in a cool place with a permissible temperature of +2 to +24°C. The test ends at 6 am, when the patient collects the last portion of urine and performs weight control. All containers are taken together and sent with a completed directions and notepad to the laboratory. There, the analysis takes 1-3 days.

Urine collection rules

The patient spends 24 hours collecting urine for analysis. In the morning, before 09.00 o'clock, the subject must empty himself into the toilet as much as possible.

Next, after 09.00 hours, a 3-hour urine collection for analysis begins:

09.00 – 12.00 – 1 portion is taken, the patient must urinate completely.
12.00 – 15.00 – collection of 2 servings.
15.00 – 18.00 – collection of 3 servings.
18.00 – 21.00 – collection of 4 portions.
21.00 – 24.00 – collection of 5 portions.
24.00 – 03.00 – collection of 6 portions.
03.00 – 06.00 – collection of 7 portions.
06.00 – 09.00 – collection of 8 portions.

All 8 portions of urine are collected in an individual container. The patient measures the volume of each 3-hour urine sample and records the data on the container label. If during the time allotted for urine collection he does not have the urge to urinate, then the container is returned empty. There is no need to wake up a sleeping person to collect the analysis.

The patient brings 8 containers with collected urine to the clinical diagnostic laboratory. Each tube must be labeled indicating the number of the 3-hour portion, the time interval and the volume of liquid received. For example, 3 servings, 200 ml, 15.00-18.00 or 6 servings, 0, 24.00-03.00.

Indications for the study

Urine analysis according to Zimnitsky is prescribed to both adults and young children, and especially often to expectant mothers. During pregnancy, the fluid balance in a woman’s body changes to meet the needs of the growing fetus, and her kidneys are forced to temporarily work for two. Alarming results of a general urine test, the presence of glucose, protein, increased levels of leukocytes, as well as edema, severe toxicosis and surges in blood pressure - all this is a reason to conduct a Zimnitsky urine test in pregnant women.

As for other categories of patients, the indications for them are as follows:

Violation of urination – frequent urge, prolonged absence of urine, abnormally small or large volumes of urine;
Painful sensations during or after urination, pain in the lower abdomen or back;
Changes in the color, consistency or smell of urine, the presence of pathological impurities in it (foam, flakes, blood, pus);
Constant thirst;
Hyperhidrosis (excessive sweating);
Systematic occurrence of edema;
Dizziness, weakness, headaches, fainting;
Rapid or rare heartbeat, chest pain;
Cold extremities, sticky sweat, attacks of fear;
Poor results of other tests (general or biochemical blood test, general urine test);
Already existing diagnoses - diabetes mellitus, glomerulonephritis, amyloidosis, liver cirrhosis, renal or heart failure, hypertension or hypotension, heavy metal poisoning, and so on - to determine the severity of the disease or control the progress of treatment.

Technique for taking analysis in vacuum tubes

Take a urine sample into a prepared container, insert the thin end of the holder into it and mix the liquid. Then rest the holder against the bottom of the container and insert the needle of the holder into the lid of the test tube without removing it. You need to press lightly so that the holder needle pierces the lid, wait until the test tube is full and unhook it from the holder.

The analysis must arrive at the laboratory no later than 24 hours; the sample can be transported at a temperature not lower than + 2 C° and not higher than + 24 C°. Material for research

8 servings of daily urine. Every 3 hours, including at night, the subject must collect biological material in a separate container.