urine concentration test

The urine concentration dilution test is to observe the ability of the distal renal tubule to concentrate urine in the state of water shortage. The function of the urine concentration of the distal tubule can be understood by measuring the specific gravity of the urine. In a normal urine sample of 3 times, the relative density is >1.026 (the elderly is above 1.020); the relative density of urine <1.020 means that the kidney is poorly concentrated. When the renal function is extremely damaged, the highest relative density of urine is 1.010; when uremia, the relative density of urine is 1.010~1.012; glomerulonephritis, pyelonephritis, hypokalemia and hyperkalemia nephropathy, etc. . Basic Information Specialist classification: urinary examination classification: urine / kidney function test Applicable gender: whether men and women apply fasting: not fasting Analysis results: Below normal: Found in diabetes insipidus, chronic nephritis. Normal value: Relative density of urine: 1.015-1.025 Above normal: Found in dehydration, diabetes, acute nephritis. negative: Positive: Tips: Maintain a normal diet and sleep. Severe renal failure, uremia (no water can aggravate the condition) is not suitable for this examination. Normal value 1.015~1.025, when it is restricted to drinking water, it can reach 1.025 or above. Clinical significance 1, increased: seen in dehydration, diabetes, acute nephritis. 2, lower: seen in diabetes insipidus, chronic nephritis. Urine specific gravity refers to the ratio of urine to the same volume of pure water at 4 ° C, depending on the concentration of dissolved substances in the urine, proportional to the total amount of solids, commonly used to measure the function of kidney concentration and dilution. In the case of non-aqueous metabolic disorders, high specific gravity can be found in dehydration, proteinuria, diabetes, acute nephritis, high fever, and the like. Isotonic urine occurs in chronic renal insufficiency, and the specific gravity is often fixed at 1.020 ± 0.003. In recent years, the specific gravity of urine has been replaced by the amount of urine permeation. Urinary specific gravity <1.010 is hypotonic urine, seen in impaired renal concentrating function, such as chronic glomerulonephritis, acute nephritis, polyuria, uremia and polyuria. Specific gravity can be used as a reference for the identification of diabetes and diabetes insipidus. The former has a large amount of urine and a high proportion. The latter has a large amount of urine and a low specific gravity. Low results may be diseases: high dehydration results may be diseases: uremia considerations Taboo before the test: maintain a normal diet and sleep. Inspection requirements: urine specific gravity is susceptible to a variety of factors, such as urine protein, sugar and other macromolecular substances, renal blood flow and endocrine function status. The high specific gravity of the high protein diet increased; the low protein, less salt diet, the proportion of malnutrition urine decreased. Urine osmotic pressure is less interfered by the above factors. The specific gravity of the urine is measured at 15 °C, the urine temperature is ±3 °C, the specific gravity reading should be ±0.003; the urine protein is +10 g/L, and the specific gravity reading should be -0.003. Inspection process Improved Fishberg method: 1. Eat a high-protein, low-liquid diet at 18:00 on the 1st of the test, the liquid content is 200ml, and then fast until the end of the test. 2. All night urine is discarded. 3. The bladder was evacuated from the morning of the test day, the urine was discarded, and the bed was continued. After that, the urine was urished once a day for 3 times. The urine specimens were placed in the container, and the urine volume, specific gravity and osmotic pressure were measured. The venous blood can be simultaneously measured for Posm. 4. Calculate the Uosm/Posm ratio, free water removal rate (CH2) or pure water removal rate of each urine, and calculate the formula and steps: V=CH2O+Cosm; CH2O=V-Cosm; Cosm=(Uosm/Posm) · V; CH2O = VV · (Uosm / Posm); = V · (1-Uosm / Posm); where V = urine volume (ml / h), composed of two parts of CH2O and osmotic concentration clearance (Cosm). Not suitable for the crowd Severe renal failure, uremia. Adverse reactions and risks Patients with severe renal failure and uremia: water ban can aggravate the condition.