[Recent advances in laboratory tests for liver diseases]

Many tests for hepatitis C virus (HCV) infection have been developed and have proved useful for prevention of post-blood transfusion hepatitis C. However, there are at least 4 genotypes of HCV and the predominant type is different among countries. None of the tests using antigens from one genotype are sensitive in detecting the antibodies against another genotype. More sensitive tests using a more stable part of the HCV RNA sequences such as 5'-noncoding region must be developed for clinical use. Automated PCR methods and DNA sandwich hybridization methods using branched DNA amplification multimers may be candidates. Recently a hepatocyte growth factor test has been developed in Japan. Multicenter trials of this test reveal that it is useful for assessment of acute severe hepatitis. Tests for collagen type IV, fibronectin receptor, and prolyl hydroxylase have been reported useful for assessment of liver fibrosis. However, serum prolyl hydroxylase is prone to increase in response to hepatocellular damage as well as fibrotic processes. Enzymatic methods for determination of branched amino acids and tyrosine have been developed. The molar ratio of branched amino acids to tyrosine seems to have same pathophysiological meaning as the ratio of branched amino acids to aromatic amino acids (Fischer ratio) in assessment of liver cirrhosis. Lidocaine test is reported to be useful for predicting survival of transplanted liver and also assessing the function of the cirrhotic liver. Profiles of alpha-fetoprotein subfractions based on lectin-reactivity and galactosyl transferase II isoenzyme have been reported to be useful for detecting hepatocellular carcinoma but this remains to be proved.