Enzyme activities of collagen peptidase (CP), monoaminoxidase (MAO) and N-acetyl-beta-D-glucosaminidase (beta-NAG) as fibrosis marker in chronic liver diseases.

The activities of enzymes collagen peptidase (CP), monoaminoxidase (MAO) and N-acetyl-beta-D-glucosaminidase (beta-NAG) in the serum are related to the development of hepatic fibrosis. These enzymes were determined in the sera of 121 liver-biopsied patients who were subdivided by morphological criteria into 4 different grades of fibrosis (0 to greater than or equal to 3). CP shows the best correlation with the extent of fibrosis. beta-NAG, indeed, bears of relationship to the morphologically proven extent of fibrosis, however, significant increases in activity are also encountered in patients with liver diseases, but without liver fibrosis. The validity of these fibrosis markers is calculated in order to differentiate between low- and high-grade fibrosis. With a sensitivity of 86% and a specificity of 92%, CP possesses the best predictive value of 85.7%. The results can still be improved by the combination of CP and beta-NAG.