Analytic and diagnostic differences in measurement of urinary proteins using pyrogallol red or blue comassie

The purpose of the study was to compare pyrogallol red (PR) and blue Coomassie (BC) for quantification of proteinuria in dogs, and to assess whether these methods affect patient’s classification as proteinuric or not. The concentration of urinary protein (UP) was determined using PR and BC on 337 urine samples. Urinary creatinine (UC) was also measured and the urinary protein to creatinine ratio (UPC) was calculated. The UP and the UPC obtained with PR and BC were compared to each other using a Wilcoxon signed rank test and method agreement using Passing-Bablok and Bland-Altman tests. The concordance of methods in classifying samples as non proteinuric (NP, UPC0.5) was assessed using the Cohen’s kappa test. PU and UPC were significantly higher (P 0.5) is acceptable