Hepatitis B Serology

Question 1

What are the antigens and what do they mean?

Answer 1

• 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 present > 6 months, implies chronic disease (i.e. Infective)
• Anti-HBs implies immunity (either exposure or immunisation). It is negative in chronic disease

Positive Anti-HB’s’ = ‘Safe’ (Previous vaccination)

• Anti-HBc implies previous (or current) infection, can get two types IgM or IgG
• IgM anti-HBc appears during acute/recent hepatitis B infection IgM –> an infection in the Moment (acute)
• IgG anti-HBc persists, IgG –> The infection is a Grandpa, has been around for a while

Positive Anti-HB’c’ = Caught (Currently infected)

• HbeAg results from breakdown of core antigen from infected liver cells as is, therefore, a marker of infectivity. Marker of HBV replication and infectivity

Question 2

Example results

Answer 2

• 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