vi medicine informatics




The period between disappearance of HBsAg and appearance of HBsAb is known colloquially as the “window period.” While hepatitis B (HB) surface antibodies are being produced, their levels are less than that of HB surface antigens. Therefore, all available HB surface antibodies are bound to HB surface antigens and are undetectable. When these antibodies are produced in excess of their corresponding viral antigens, they will then be detected in serum. Hepatitis B core antibody (HBcAb or anti-HBc) is the earliest detectable immune response after hepatitis B exposure and is a response to the core protein of the hepatitis B particle. IgM anti-HBc is the sole marker of acute (because it is IgM) hepatitis B infection during the window period. Anti-HBeAg is also present during the window period, but because it can be produced temporarily during acute, or more constantly during chronic infection, its presence is not useful in determining if the infection is chronic or acute.

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