Question

Which of the following is a marker for recent (acute) hepatitis B infection?

• A. IgM anti-HBs
• B. IgM anti-HBc
• C. HBeAg
• D. HBsAg

Hint:

IgM anti-HBc is positive early and is the only marker seen during the window period of acute hepatitis B.

Answer 1

The Correct Option is B

Hepatitis B markers rise and fall at different times, and this question asks which one specifically flags a recent, that is acute, infection rather than an old or chronic one.

1. IgM anti-HBs: Anti-HBs is mostly an IgG response that appears late, after the virus clears, and shows immunity rather than a fresh infection, so it does not fit.
2. IgM anti-HBc: Appears soon after infection and fades within about six months. It is also the only marker present during the window period, when HBsAg is gone and anti-HBs has not yet risen. This makes it the clearest sign of a recent infection.
3. HBeAg: Marks active virus replication and high infectivity but is seen in both acute and chronic active disease, so it cannot separate recent from long standing infection.
4. HBsAg: Confirms the virus is present but stays positive for years in chronic carriers, so its presence alone does not prove the infection is new.

Because IgM anti-HBc rises early, fades by about six months, and fills the window period gap left by the other markers, it is the specific sign of recent hepatitis B infection.

Let's summarize:

• HBsAg and HBeAg can be positive in both acute and chronic infection.
• IgM anti-HBc is short lived and marks recent infection specifically.
• IgM anti-HBc is the only positive marker during the diagnostic window period.

The marker for recent hepatitis B infection is IgM anti-HBc.