Comparison of the optimized direct spectrophotometric serum prolidase enzyme activity assay method with the currently used spectrophotometric assay methods and liver fibrosis indexes to distinguish the early stages of liver fibrosis in patients with chronic hepatitis B infection.

The aim of this study was to optimize the currently used direct spectrophotometric serum prolidase enzyme activity (SPEA) assay method and compare its diagnostic accuracy with current precipitation and direct spectrophotometric assay methods, AST-to-ALT ratio, age platelet index, AST-to-platelet ratio index, cirrhosis discriminate score, Doha score, FIB-4, FibroQ, fibrosis index, Goteborg University Cirrhosis Index , King’s score, and Pohl score for distinguishing Ishak F0 from F1–F3 in patients with chronic hepatitis B (CHB) infection. Liver biopsy results from 112 patients were included in this study.  The SPEA values were 529 (292–794) U/L, 671 (486–927) U/L, and 1077 (867–1399) U/L with the precipitation, current, and optimized direct spectrophotometric assay methods, respectively. According to multivariate logistic regression analysis optimized direct spectrophotometric SPEA was the only statistically significant parameter to predict the early stages of liver fibrosis.  Optimized direct spectrophotometric SPEA assay method could be used to distinguish early stages of liver fibrosis in patients with CHB infection instead of the currently used spectrophotometric SPEA assay methods and other evaluated liver fibrosis indexes.