The study of the child's urine according to the Zimnitsky method allows you to assess the function of the kidneys. Why should a child be assigned such an analysis, how does it differ from other similar analyzes, and what problems does it help to identify?
Indications
Usually, a child's urine test according to Zimnitsky is carried out to detect renal failure. Also, this test is prescribed if diabetes mellitus, glomerulonephritis, or heart failure is suspected.
Features:
The main difference between the analysis according to Zimnitsky and other urine tests is the emphasis on determining the amount of urine excreted per day, as well as the density of each portion of it, which indicates the concentration of substances dissolved in it. This sample does not investigate other indicators.
How to collect the analysis?
The analysis provides for collection during the day in 8 containers, each of which must get urine over a 3-hour period. Usually they start collecting it at 9 am. Before each urination, the child's genitals should be washed.
All containers are sent to the laboratory, even if some of them are empty. If for some period of time there is more urine than fits in the container, take another jar and mark the same time period on it.
You also need to separately note the amount and time of the fluid you drink. Store collected test material in a cool place, such as a refrigerator.
Training
On the eve of the analysis, you should not drink too much fluids, so as not to induce artificial polyuria and reduce the density of urine. It is also undesirable to eat foods with dyes, salty and spicy foods, which can increase thirst. In addition, diuretics are excluded for the duration of the study.
Normal values
Normally, when analyzed according to Zimnitsky:
- During the daytime, more urine is excreted than at night (50-75% of all urine is excreted during the day).
- The density of different portions must vary. Fluctuations between the maximum and the lowest density during the day should be greater than 0.007.
- After drinking the liquid, after 1-2 hours the amount of urine increases.
- At least 65-80% of the liquid drunk within 24 hours is removed.
Reasons for deviations
Analysis according to Zimnitsky can reveal:
- Density changes. The indicator may be higher with a lack of fluid in the child's diet, the first stages of glomerulonephritis or diabetes mellitus. The density of urine will be lower if the child has renal or heart failure, pyelo- and glomerulonephritis, and diabetes insipidus.
- Polyuria - an increased amount of urine excreted per day. This symptom can be with diabetes and nephritis.
- Oligouria - reduced amount of urine excreted per day. This symptom indicates a filtration disorder with kidney damage. It is characterized by toxic kidney damage, hemolytic anemia, or very low blood pressure.
- Nocturia - a condition when more than 50% of the total diuresis is excreted at night. This symptom is typical for diabetes mellitus and heart failure.
- Hyperisostenuria - a condition when reabsorption is enhanced in the tubules, as a result of which the density of urine is higher, and its amount is less. Such a result may indicate diabetes mellitus or glomerulonephritis.
- Hypoisostenuria - a state when there are almost no density fluctuations during the day (they are not more than 0.007). It indicates chronic kidney failure, when reabsorption is impaired in the tubules.
