Hepatitis B serology

Interpreting hepatitis B serology is a dying art form which still occurs at regular intervals in medical exams. It is important to remember a few key facts:

• surface antigen (HBsAg) is the first marker to appear and causes the production of anti-HBs
• HBsAg normally implies acute disease (present for 1-6 months)
• if HBsAg is present for > 6 months then this implies chronic disease (i.e. Infective)
• Anti-HBs implies immunity (either exposure or immunisation). It is negative in chronic disease
• Anti-HBc implies previous (or current) infection. IgM anti-HBc appears during acute or recent hepatitis B infection and is present for about 6 months. IgG anti-HBc persists
• HbeAg results from breakdown of core antigen from infected liver cells as is, therefore, a marker of infectivity. Marker of HBV replication and infectivity

Example results

• previous immunisation: anti-HBs positive, all others negative
• previous hepatitis B (> 6 months ago), not a carrier: anti-HBc positive, HBsAg negative
• previous hepatitis B, now a carrier: anti-HBc positive, HBsAg positive

HBsAg = ongoing infection, either acute or chronic if present > 6 months anti-HBc = caught, i.e. negative if immunized

https://www.youtube.com/watch?v=sndUqE1QAKU