The Hepatitis B Surface Antibody (HBsAb) test is a rapid chromatographic immunoassay for the qualitative detection of Hepatitis B Surface Antibody in serum or plasma. The HBsAg Rapid Test Cassette is a lateral flow chromatographic immunoassay for the qualitative detection of Hepatitis B surface antigen (HBsAg) in human whole blood, serum or plasma.

Viral hepatitis is a systemic disease primarily involving the liver. Most cases of acute viral hepatitis are caused by Hepatitis A virus, Hepatitis B virus (HBV) or Hepatitis C virus. The complex antigen found on the surface of HBV is called HBsAg. The presence of HBsAg in whole, blood, serum or plasma is an indication of an active Hepatitis B infection, either acute orchronic.

In a typical Hepatitis B infection, HBsAg will be detected 2 to 4 weeks before the ALT level becomes abnormal and 3 to 5 weeks before symptoms or jaundice develop. HBsAg has four principal subtypes: adw, ayw, adr and ayr. Because of antigenic heterogeneity of the determinant, there are 10 major serotypes of Hepatitis B virus.

The antibody to HBsAg, HbsAb may not become detectable for 3 - 6 months after acute infection. It is as the marker of immunity to HBV. As a result, vaccination against HBV was introduced to control the morbidity and mortality associated with the virus. As part of the World Health Organization (W.H.O.) program for the control of Hepatitis B, many people, especially newborn infants, receive vaccination.