Higher Cut-Off Index Value of Immunoglobulin M Antibody to Hepatitis B Core Antigen in Taiwanese Patients with Hepatitis B

Background: The cut-off index value of immunoglobulin M (IgM ) antibody to hepatitis B core antigen (anti-HBc; AxSYM CORE -M, Abbott) for diagnosing acute hepatitis B is 1.2. A high false-positive rate of IgM anti-HBc was observed in acute flare-ups of chronic hepatitis B in Taiwanese patients. Thus the purpose of the present paper was to study the optimal index value of IgM anti-HBc in Taiwanese subjects. Methods: The peak index values of 42 IgM anti-HBc-positive patients were collected. There were 20 acute hepatitis B patients and 22 patients with chronic hepatitis B with acute flare. The biochemical, virological, and serological data were obtained . Results:There were significant differences in mean age (36 vs 47 years, P = 0.01), serum alanine aminotransferase level (2042 U/L vs 1193 U/L, P = 0.02) and peak index value of IgM anti-HBc (2.9 vs 1.5, P 1.2. The optimal cut-off index value to differentiate acute hepatitis B from chronic hepatitis B with acute flare was 2.4-2.5, with a sensitivity of 90% and specificity of 90%. Conclusions:The cut-off index value of IgM anti-HBc to differentiate acute hepatitis B from chronic hepatitis B with acute flare among Taiwanese patients should be set at 2 . 4-2.5 instead of 0.8-1.2.(c) 2006 Blackwell Publishing Asia Pty Ltd