Screening of Proteinuria by Urinary Specific Gravity in Nephrotic Syndrome

Abstract

Background: Nephrotic syndrome is the commonest glomerular disease in children and is often characterized by multiple relapses. Twenty-four hours urinary protein estimation is the accepted method used in the quantification of proteinuria, but it’s a time-consuming, inconvenient and cumbersome and difficult in very young children. This study emphasized screening of proteinuria by urinary specific gravity in nephrotic syndrome. Material & Methods: This cross-sectional study was conducted in the Department of Pediatric Nephrology (NIKDU), Dhaka, Bangladesh from October 2019 to June 2021. A total of 153 patients with nephrotic syndrome were enrolled as the study subjects after taking written consent. Urine samples were collected for both 24 hours and spot for estimation of urinary protein, urinary creatinine (Ucr) and specific gravity by dipstick method. Spot and 24-hour urinary protein creatinine ratio (PCR) were also estimated. From urinary specific gravity, estimated urinary creatinine (estUcr) and estimated urinary protein creatinine ratio (est PCR) were measured. A descriptive method was used and data were processed by using SPSS version 22.0. Results: Among 153 study subjects, the maximum (44.4%) were from the 2-5 years age group followed by 58 (37.9%) from 5-10 years and 27 (17.6%) from >10 years age groups. Boys (61.4%) were more predominant than girls (38.6%) in number. Spot and 24-hour urinary specific gravity have a significant positive correlation with urinary creatinine. Urinary creatinine was estimated by using the equation (Ucr = 1.25×1000 Usg – 1.24×1000). Both spot and 24-hour estimated urinary PCR (est PCR) measured by using urinary specific gravity have a significant positive correlation with corresponding urinary PCR. Conclusion: This study concluded that spot urinary specific gravity has a significant positive correlation with spot urinary protein and spot urinary creatinine. PCR can be estimated from dipstick urinary specific gravity instead of urinary creatinine in the cumbersome laboratory. Therefore, the study may establish an easy, rapid, inexpensive and alternative method for the detection of proteinuria in nephrotic syndrome so that it will help for early detection of relapse and prevent further complications related to nephrotic syndrome.