Non-clinical sciences/Lab medicine · Serology interpretation

Hepatitis B serology

What it means

HBsAg = current infection (acute or chronic). Anti-HBs = immunity (vaccine or cleared infection). Anti-HBc IgM = recent/acute (window). Anti-HBc IgG (total) = past exposure (not vaccine). HBeAg = high infectivity/replication. Vaccinated only → anti-HBs positive, everything else negative.

Worked example

Anti-HBs positive with anti-HBc negative = vaccinated (not previously infected).

In the exam

A health-care worker's serology shows anti-HBs positive but HBsAg and anti-HBc both negative.

What settles it

Anti-HBc (core) is positive after natural infection but NEGATIVE after vaccination — it distinguishes immunity-from-infection vs immunity-from-vaccine.

Classically confused with

LFT patterns — hepatocellular vs cholestatic

Source: StatPearls — Hepatitis B serology