Creatinine is a product of muscle metabolism. It is produced at a nearly constant rate and is excreted in the urine. Because of its constant rate of production, the amount of creatinine in the urine is an indirect measurement of kidney function (glomerular filtration rate). A 24-hour collection of urine is the most accurate way to assess renal function with creatinine. This test is also useful for following up the effect of a course of treatment in cases of acute glomerulonephritis, or to identify glomerular dysfunction. Urine creatinine will FALL if kidney function is significantly reduced, or in muscle disease (especially muscular dystrophy). See Creatinine, Serum and Creatinine Clearance, Serum & 24 Hrs Urine
State 24 Hrs urine volume. Do not add preservative.