Quantitating proteinuria using the urinary protein creatinine index.

Quantitating proteinuria by the 24 hour urine protein estimation (24 HUP) is cumbersome and fraught with error. We therefore investigated the relationship between the 24 HUP and the protein creatinine index (PC!) in a spot morning urine in 20 normal controls and 63 urine samples from 58 patients. The latter had proteinuria ranging from 0.2 gm to 31.6 gm and serum creatinines between 54 to 837 umol/L. The Pearson correlation coefficients between PCI and 24 HUP, PCI and 24 HUP excretion per kg, PCI and 24 HUP excretion per 1.73m2 were 0.87,0.87,0.87 and 0.91 respectively (p < 0.001 in each case). The PCI fornormal controls (mean 24 HUP 0.2 gm) was < 0.02 gm/mmol. That for nephrotic range proteinuria (24 HUP> 3 gm) was> 0.45 gm/mmol, Our results agree with those of other workers and show that a spot morning urine PCI (preferably corrected to 1.73m2) can and should replace a 24 HUP estimation.