Estimation of 24 hour protein excretion from single random urine specimen

The product of protein/creatinine ratio (in a random urine specimen) and estimated daily urinary creatinine excretion were evaluated as a function of 24 h urinary protein excretion in 40 patients with pathology proteinuria having varying grades of renal function. An excellent correlation was found between the results obtained by this method and those from the standard 24 h urine collection method in healthy controls (r = 0.99) and in patients with normal (r = 0.88) or mild to moderately impaired renal function (r = 0.99). However, this method did not give a good measure of quantitative proteinuria in patients with advanced renal failure (r = 0.56), possibly due to decreased urinary excretion of creatinine in patients with advanced renal failure as compared to the estimated value. The product of protein/creatinine ratio and estimated daily urinary creatinine excretion thus gave a quick and alternate reliable method of estimating 24 h proteinuria in patients having normal or mild to moderately impaired renal function. However, this method is not suitable for patients with advanced renal failure.