Zimnitsky Urine Test
The Zimnitsky urine test is a laboratory study aimed at assessing the functional state of the kidneys, particularly their ability to concentrate and dilute urine. The method involves collecting urine over 24 hours at 3-hour intervals, resulting in 8 urine samples, each labeled with the collection time.
Main parameters evaluated during the test:
- Urine volume in each portion (3-hour interval)
- Specific gravity of each urine portion
- Total 24-hour diuresis, daytime and nighttime diuresis
These indicators allow evaluation of the kidney’s concentrating function: with normal function, daytime urine volume exceeds nighttime volume, and specific gravity ranges between 1.005–1.025 for daytime urine and up to 1.035 for nighttime urine. If the specific gravity is close to plasma density (about 1.010), it indicates impaired concentrating ability of the kidneys (isosthenuria).
Indications for the test:
- Suspected renal failure
- Chronic glomerulonephritis and pyelonephritis
- Diagnosis of diabetes insipidus
- Hypertensive disease
- Monitoring treatment effectiveness of kidney diseases and chronic condition follow-up
Preparation for the test:
- Maintain usual fluid intake
- Avoid alcohol and foods that alter urine color (e.g., beets, asparagus)
- Refrain from medications that may distort results
- Perform thorough hygienic washing before urine collection
Significance of the test:
The Zimnitsky test helps detect water-electrolyte balance disorders, assess renal concentrating function, and timely diagnose kidney and urinary tract diseases, which is crucial for prescribing adequate therapy and monitoring the patient’s condition.