Serum angiotensin converting enzyme and C4 protein of complement as a combined diagnostic index in alcoholic liver disease.

Diagnosis of liver cirrhosis relies on hepatic biopsy. So far, attempts have failed to achieve a serologic test that differentiates cirrhosis from other hepatic conditions. The aim of this work was to assess the diagnostic value of the ratio of serum angiotensin converting enzyme activity (SACE) and the levels of protein C4 of serum complement (SACE/C4) in differentiating cirrhotic from noncirrhotic alcoholic liver diseases. In this study, 68 active alcoholic patients (17 with fatty liver or minimal changes, 11 with acute alcoholic hepatitis and 40 with cirrhosis) were included. Twenty healthy subjects were studied as a control group. Liver biopsy was performed in all patients. SACE levels were significantly higher in the group with cirrhosis when compared with the group of patients without cirrhosis and the control. On the other hand, serum C4 level decreased as liver damage progressed. SACE values above 25 IU/l had a sensitivity of 92.5 percent (95 percent confidence interval, 87.5 to 97.5) and a specificity of 79 percent (95% percent confidence interval, 70.5 to 87.5), in detecting those patients with liver cirrhosis. The sensitivity further increased to 95 percent (95 percent confidence interval, 90.5 to 99.5) and the specificity to 100 percent when the SACE/C4 ratio was used and a cutoff point of 145 was chosen. To conclude, in alcoholics SACE is specifically elevated in patients with cirrhosis, and the SACE/C4 ratio is a excellent biochemical index for the diagnosis of cirrhosis in alcoholic patients.