Spot urine protein/creatinine ratio is associated with 24-hour proteinuria and serum albumin

Abstract

Proteinuria is an important risk factor for renal and cardiovascular diseases. In nephrology practice, treatment decisions are made according to proteinuria levels. Inconstinencies in the measurements of proteinuria with different methods such as urinalysis, spot urine protein to creatinin ratio (PCR) and 24-hour-urine proteinuria lead to confusion in the management of the patients. Herein, we aimed to compare these three proteinuria measurement methods within themselves, and serum albumin levels,and evaluate existing correlations. A total of 1038 urine tests were evaluated. Urinalysis was performed using FUS-200/H-800 full-automatic urinalysis system. Spot urine PCR and 24-hour-urine proteinuria were measured turbidometrically. Serum albumin concentrations were measured photometrically. Urine samples with more than 10 leukocytes or erythrocytes in urine sediments were not included in the analysis.. Proteinuria detected with urinalysis was significantly associated with spot urine PCR (r=0.75, p<0.001), 24-hour proteinuria (r=0.76, p<0.001) and serum albumin levels (r= -0.36, p<0.001). In patients with 3+ proteinuria in urinalysis, urine PCR was measured as 5.59 (2.76-9.11) g/day; 24-hour proteinuria, 4.54 (2.85-9.05) g/day and serum albumin level, 3.08±0.86 g/dL. Spot urine PCR was significantly correlated with 24-hour proteinuria (r=0.80, p<0.001). Both spot urine PCR and 24-hour proteinuria were significantly and negatively correlated with serum albumin levels (r=-0.54, p<0.001 and r=-0.54, p<0.001, respectively). Spot urine PCR obtained from both morning and afternoon samples were significantly associated with 24-hour proteinuria (r=0.83, p<0.001 and r=0.82, p<0.001 respectively). All three methods of measurement for proteinuria were significantly associated with each other and serum albumin levels. Spot urine PCR is an easy and reliable method for measurement of proteinuria. © 2016, Logos Medical Publishing. All rights reserved.