Ascitic fluid alpha 1-antitrypsin.

Ascitic fluid alpha 1-antitrypsin (AF-AAT) was compared with ascitic fluid total protein (AF-TP) and the serum-ascites albumin gradient (SAAG) in the differential diagnosis of ascites. The study included 82 consecutive patients of which 42 had cirrhosis, 8 hepatoma (with cirrhosis), and 27 malignant ascites (peritoneal 18, liver 9). The concentration of AF-AAT (milligrams per deciliter) was significantly elevated (P less than 0.001) in hepatoma (174 +/- 123), malignant liver disease (232 +/- 119) and peritoneal neoplasms (376 +/- 106) in comparison with cirrhotics (66 +/- 33). In separating ascites caused by cirrhosis or malignancy, AF-AAT (discriminating limit of 120 mg/dl) had a 96% sensitivity, 95% specificity, and 96% diagnostic efficacy, which was superior to the 87% observed for AF-TP and 86% for the SAAG. Similar results were obtained for the A/S AAT ratio but this test was not available in all patients. AF-AAT was particularly useful in patients with malignancy causing portal hypertension as assessed by SAAG (hepatoma, malignant liver disease). We conclude that AF-AAT may be a valuable parameter in the differential diagnosis of ascites.