We compared the performance of Coomassie Brilliant Blue (CBB) and Ponceau S dyes based proteinuria estimation methods with immunoturbidimetry microalbumin estimation to develop new cut-offs for proteinuria, which would help us detect diabetic nephropathy patients with better sensitivity using the above mentioned dye based methods. These proteinuria testing methods are easy to adapt in smaller laboratories typically associated with peripheral government health centers.
Urine sample was collected from 158 diabetic individuals and tested simultaneously for Urine Albumin Creatinine ratio (UACR) using immunoturbidimetry and Urine Protein Creatinine Ratio (UPCR) using Ponceau S method and CBB method. The Ponceau S method gives good correlation with immunoturbidimetry, for screening of diabetic nephropathy, at UPCR cut-off of 50mg/g creatinine. The CBB method gives higher false positives. The overall agreement of Ponceau S and CBB with immunotubidimetry is maximum at cut off 50mg/g, i.e. 91% and 84% respectively.
In conclusion, proteinuria estimation with Ponceau S method with UPCR >50mg/g creatinine, may be used for routine screening of diabetic patients to diagnose microalbuminuria.
Diabetic nephropathy screening, Proteinuria, Microalbuminuria, Ponceau S.