Diagnostic significance of serum angiotensin-converting enzyme activity in biochemical tests with special reference of chronic liver diseases.

To assess the degree of the differential ability of serum angiotensin-converting enzyme (ACE) activity as compared with 13 conventional biochemical tests, we studied 76 healthy subjects and 107 patients with chronic liver diseases. It was found that the mean values of serum ACE activity were significantly different between the healthy group and groups with liver disease. According to discriminant function analysis, the diagnostic accuracy reached 82.2% in 14 tests. In order to analyze the extent of contribution of each test to the entire diagnostic accuracy, we made an indicator of the relative decrease rate expressed as a percentage, which is 100-100 x (13-test diagnostic accuracy less one test/14-test diagnostic accuracy). The relative decrease rate of serum ACE activity was 11.4%, the largest in value. In conclusion, serum ACE activity may be one of the best discriminators to characterize chronic liver disease.