To determine whether the presence of circulating desialylated glycoproteins reflect the existence and/or the severity of liver disease, 73 patients were evaluated with liver biopsies, conventional liver function tests, and the measurement of the degree of desialylation of two glycoproteins ax-acid glycoprotein (α1-AGP) and ai-antitrypsin (α1-AT). A combination of two immunological methods, available as routine laboratory tests, was used for the determination of the desialylation of α1-AGP and α1-AT. The severity of liver disease was assessed by a clinical classification depending upon the presence or absence of four complications (jaundice, ascites, hepatic encephalopathy, and weight loss). The presence of serum desialylated α1-AGP did not allow detection of mild liver disease, but asialoon-AGP (and to a lesser extent of asialo-ai-(AT) correlated with the severity of liver disease. The sensitivity of desialylated ai-AGP in detection of severe liver disease was 65%, and its specificity was 80%.