AccuTest HBsAg Card Test - Hepatitis B Hepatitis B is a viral infection that attacks the liver and can cause both acute and chronic disease. An estimated 240 million people are chronically infected with hepatitis B (defined as hepatitis B surface antigen positive for at least 6 months). Laboratory diagnosis of hepatitis B infection focuses on the detection of the hepatitis B surface antigen HBsAg. Hepatitis B surface antigen (HBsAg) consists of lipid carbohydrate and protein elements; the protein moiety provides a marker for identification of chronic, infectious BBV infections. Hepatitis B is transmitted sexually or intravenously and has an incubation period of six months. If not diagnosed properly and in time, it can develop into acute or chronic infection, liver cirrhosis and fulminant hepatitis. This test is very useful for screening blood donors, to find out whether they are HBsAg positive before collection of blood.