Communicable diseases: hepatitis B infectivity marker: practice question

A PSM 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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PSM · Communicable diseases: hepatitis B infectivity marker

Sample item

A health worker in a dialysis unit is found HBsAg positive. Which additional marker would indicate high replication and high infectivity of the virus in her blood?

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

The answer and the reasoning

B. HBeAg

HBeAg reflects active viral replication and a high viral load, so carriers who are HBeAg positive are highly infectious. Appearance of anti-HBe usually signals lower replication. Anti-HBs indicates immunity and anti-HBc IgG indicates past or ongoing exposure.

Option by option

  • A. Anti-HBc IgG

    Anti-HBc IgG shows exposure and does not indicate how infectious the person is.

  • B. HBeAg (correct)

    Correct. HBeAg marks active replication and high infectivity.

  • C. Anti-HBe

    Anti-HBe usually indicates reduced viral replication.

  • D. Anti-HBs

    Anti-HBs is the protective antibody and indicates immunity, not infectivity.

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 PSM questions

Questions about this PSM question

What is the answer to this PSM question?

The best answer is B, HBeAg. HBeAg reflects active viral replication and a high viral load, so carriers who are HBeAg positive are highly infectious.

Why is "Anti-HBc IgG" not the answer?

Anti-HBc IgG shows exposure and does not indicate how infectious the person is.

Why is "Anti-HBe" not the answer?

Anti-HBe usually indicates reduced viral replication.

Why is "Anti-HBs" not the answer?

Anti-HBs is the protective antibody and indicates immunity, not infectivity.

What concept does this question test?

It tests Communicable diseases: hepatitis B infectivity marker in PSM. Appearance of anti-HBe usually signals lower replication. Anti-HBs indicates immunity and anti-HBc IgG indicates past or ongoing exposure.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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 Communicable diseases: hepatitis B infectivity marker?

Practise biostatistics with small calculations until sensitivity, predictive values and risk measures are automatic. Then use the flashcards and the other PSM 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.