The protein/creatinine index. A semiquantitative assessment of 24-hour protein excretion.

The 24-hour protein excretion is important in estimating the severity of a renal lesion and is used extensively for diagnostic and prognostic purposes and also to follow the response of patients to treatment. The disadvantages of timed 24-hour collections are that they are cumbersome, inconvenient, expensive, and unreliable in up to one-third of cases. The aim of this study was to correlate the protein/creatinine (P/cr) index in a random spot urine sample and protein excretion in a 24-hour urine sample from the same patient. The P/cr index was derived as follows: (Formula: see text). In the 34 patients investigated there was a highly significant correlation (r = 0.9017) between the P/cr index and 24-protein excretion. The P/cr index is a useful and quick method of assessing proteinuria in most patients with renal disease.