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24-Hour Urine: Normal Values and Creatinine Clearance Calculation
- Urine Analysis: sediment and dipstick
- Urine Analysis: urine culture
- Urine Analysis: 24-hour urine test
Indications for a 24-Hour Urine Collection
- Calculation of the creatinine clearance
- After the recurrence of renal stone disease
- Hormonal diseases and tumors of the adrenal glands
- Quantification of proteinuria in chronic renal diseases
24-Hour Urine: Standard Values
| Substance | Standard value |
| Urinary pH | 4,4–7,5 |
| Specific Gravity | 1,010–1,024 g/ml |
| Osmolality | 500–800 mosm/kg |
| Urea | 20–35 g/24 h |
| Calcium | <7,5 mmol/24 h |
| Uric acid | 0,3–0,6 g/24 h |
| Sodium | 40–140 mmol/l |
| Potassium | 40–120 mmol/l |
| Magnesium | 4–8 mmol/l |
| Chloride | 40–140 mmol/l |
| Protein | < 150–300 mg/24 h |
| Cortisol | < 100 mg/1,73m2/24 h |
| Aldosterone | < 30 μg/24 h |
| Vanillylmandelic acid | < 6,5 mg/24 h |
| Metanephrines | < 0,8 mg/24 h |
Calculation of the Creatine Clearance
The concentration of creatinine is measured in the urine from the 24 h urine test (Ucrea in mg/dl) and in the serum (Screa in mg/dl). In addition, the urine volume (Uvol in ml) is measured with the collection period (24 h = 1440 min). The creatinine clearance (Clcrea) can be calculated using the following formula:
Creatinine clearance (ml/min) = (Ucrea × Uvol)/(Screa × 1440)
Cockroft and Gault Formula for Creatinine Clearance
An estimation of the creatine clearance (after Cockroft and Gault) is possible with serum concentration (mg/dl), sex (factor F=72 for men and F=85 for women), weight (kg), and age (years) using the following formula:
GFR = -(140-age)×weight / (F× Screa)
| Urine culture | Index | Examinations |
Index: 1–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
References
D. W. Cockcroft and M. H. Gault, “Prediction of creatinine clearance from serum creatinine.,” Nephron, vol. 16, no. 1, pp. 31–41, 1976.
Deutsche Version: 24 h-Urin