A semiautomatic analyzer for urinary protein assay and a software program for classifying renal injury using cellulose acetate electrophoresis

The purpose of this study was to develop and evaluate a semiautomatic analyzer for total urinary protein assay and to develop a software program for identifying the affected part of the kidney by using data obtained by cellulose acetate electrophoresis (CAE) with silver staining. The limit of detection of this semiautomatic analyzer was 2.5 mg/L, and the assay precision was good, with a coefficient of variation (CV) less than 10%. Moreover, there was a good correlation between the results obtained by using this semiautomatic analyzer and the manual method. The urinary protein fractions of patients who were diagnosed with renal disease on the basis of renal biopsy were analyzed by performing CAE with silver staining. The relative mobility (RM) of several bands in the β fraction was calculated. The algorithm of the method used for calculating RM was programmed, and the RM ranges detected in several major protein bands were incorporated in the programmed software to classify the types of renal disorders. The programmed software could be used to classify the types of nephropathy in the case of diabetic patients with albumin concentrations of 30 mg/gCre or less. This semiautomatic analyzer can help detect nephropathy in early stages, and the urinary protein fraction analysis software can help determine the type of renal disorder in diabetic patients before microalbuminuria is detected, thus facilitating early treatment.