The Correlation of Urine Protein/osmolality and Protein/creatinine Ratio as Predictor of 24-hour Urinary Protein Excretion

Abstract

Background: The drawback of 24-hour urine collection is that it is troublesome, takes a lot of time, and is inaccurate because of collection errors and improper timing. The research in the Indian adult population about the correlation of spot urine protein/osmolality ratio (UPOR) and spot urine protein/creatinine ratio (UPCR) as a predictor of 24-hour urinary protein excretion is lacking.

Objectives: To study the correlation of spot UPOR and spot UPCR as the prognosticator of 24-hour urinary protein excretion.

Materials and methods: The present cross-sectional observational study was undertaken on 50 patients >18 years of age and of either sex who presented with proteinuria (dipstick test or urine routine) and were advised 24-hour urine protein examination. A 24-hour urine was collected for protein analysis starting from any time of day. Random urine samples were collected and processed for protein, creatinine, and osmolality. The spot UPOR and UPCR were calculated. The sensitivity and specificity were determined. Pearson's correlation was used to find the correlation.

Results: There was a statistically significant positive correlation of UPOR and UPCR (r = 0.418 and r = 0.512, respectively) with 24-hour urinary protein excretion. The sensitivity and specificity of UPOR to predict 24-hour urinary protein at cutoff point 1.32 was 82.3% and 81%, respectively. The sensitivity and specificity of UPCR to predict 24-hour urinary protein at cutoff point 1.09 was 87 and 86%, respectively.

Conclusion: For the medical determination of proteins in urine, spot UPOR and UPCR are suitable, cheap, and dependable methods that can substitute the measurement of 24-hour urine protein.