HEPATITIS B SURFACE ANTIGEN (HbsAg)

OD Ratio

• Negative : ≤0.90
• Equivocal : 0.91-1.10
• Positive : ≥1.11

• Hepatitis B surface Ag detects protein that is present on the surface of the virus. it is used to screen for, detect, and help diagnose acute and chronic HBV infections
• Undetectable in the blood during the recovery period; it is the primary way of identifying those with chronic infections, including "HBV carrier" state.
• It is the earliest indicator of HBV infection, detectable as early as 14 days before the onset of symptoms
• HbsAg persistent over more than 6 months signifies a carrier stage
• Helps in screening of blood and organ donors, in the differential diagnosis of hepatitis and fulminant hepatitis
• Transmission is due to parental contact through the exchange of blood and blood products, sexual contact, and perinatal spread from mother to new born. Clinical manifestations range from mild asymptomatic infections to severe fulminant hepatitis. Antibodies to these appear generally after HBsAg has been cleared from the blood stream, usually six months after infection, and its presence represents recovery and lifelong immunity. In Chronic carriers no antibody is present

• When there is s/s of acute hepatitis
• When clinical features suggest chronic hepatitis
• In screening of blood and organ donors
• In Differential diagnosis of fulminant hepatitis