Estimation of 24 h Urine Protein Versus Spot Urine Protein Creatinine Ratio in Patients with Kidney Disease

Abstract

This cross-sectional study was undertaken to compare 24-h urine protein estimation with spot urine protein-creatinine ratio (PCR). 72 patients having proteinuria of > 150 mg/day were included in this study. 24-h urine total protein (UTP) test were also asked to give their mid-morning spot urine sample the following day for urine protein-creatinine ratio. The subjects were grouped according to their UTP into Groups as described follows: Group A < 1 g/day, Group B 1–3.5 g/day and Group C > 3.5 g/day. Pearson’s correlation (r) and paired Student’s T test were done. The paired T test showed no difference in the UTP and PCR in the subgroup having qualitative protein of zero and in group A. There was no agreement between the two methods used for quantitation. In the overtly proteinuric patients, the correlation between the UTP and PCR was positive in group A which was statistically significant (p = 0.05) whereas it was not significant (p = 0.07) in group B. Though there was a negative correlation in the massive proteinuria group C it was not significant (p = 0.65). Our study demonstrates that spot PCR can be reliable parameter for initial diagnostic criterion of proteinuria but for follow-up measurements and for proteinuria > 0.5 gm/day, 24-h UTP is the single most accurate measurement of protein excretion.