Virology: hepatitis B serology: practice question

A Microbiology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Microbiology · Virology: hepatitis B serology

Sample item

A man with acute jaundice 10 weeks after a tattoo has these results: HBsAg negative, anti-HBs negative, IgM anti-HBc positive. How should this be interpreted?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Window period of acute hepatitis B

In acute hepatitis B, HBsAg may fall below detection before anti-HBs rises, leaving a window in which only IgM anti-HBc is present. Detecting IgM anti-HBc therefore diagnoses recent infection when HBsAg is negative. Anti-HBc is not produced by vaccination.

Option by option

  • A. Window period of acute hepatitis B (correct)

    Correct. Isolated IgM anti-HBc fills the window between HBsAg clearance and anti-HBs appearance.

  • B. Immunity after hepatitis B vaccination

    Vaccination produces anti-HBs alone, with no anti-HBc.

  • C. Recovered past infection with natural immunity

    Recovered infection shows anti-HBs with IgG anti-HBc rather than IgM anti-HBc.

  • D. Chronic hepatitis B carrier state

    A carrier would be HBsAg positive for more than 6 months with IgG anti-HBc.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More Microbiology questions

Questions about this Microbiology question

What is the answer to this Microbiology question?

The best answer is A, Window period of acute hepatitis B. In acute hepatitis B, HBsAg may fall below detection before anti-HBs rises, leaving a window in which only IgM anti-HBc is present.

Why is "Immunity after hepatitis B vaccination" not the answer?

Vaccination produces anti-HBs alone, with no anti-HBc.

Why is "Recovered past infection with natural immunity" not the answer?

Recovered infection shows anti-HBs with IgG anti-HBc rather than IgM anti-HBc.

Why is "Chronic hepatitis B carrier state" not the answer?

A carrier would be HBsAg positive for more than 6 months with IgG anti-HBc.

What concept does this question test?

It tests Virology: hepatitis B serology in Microbiology. Detecting IgM anti-HBc therefore diagnoses recent infection when HBsAg is negative. Anti-HBc is not produced by vaccination.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Virology: hepatitis B serology?

Make a one-line identity card for each organism: shape and stain, defining test, toxin, disease and drug. Then use the flashcards and the other Microbiology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.