STI: HIV diagnosis in an exposed infant: practice question

A Dermatology 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.

Try it

Dermatology · STI: HIV diagnosis in an exposed infant

Sample item

An asymptomatic 8-month-old infant born to a mother with HIV has a reactive HIV antibody test. Which test confirms infection in the infant?

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

The answer and the reasoning

B. HIV DNA PCR (nucleic acid test)

Maternal IgG crosses the placenta and can persist up to 18 months, so antibody tests are unreliable in exposed infants. Virological testing by DNA PCR or other nucleic acid testing diagnoses infection.

Option by option

  • A. Western blot

    A Western blot also detects maternal antibody.

  • B. HIV DNA PCR (nucleic acid test) (correct)

    Correct. Nucleic acid testing detects the virus directly and is not confounded by maternal antibody.

  • C. Repeat ELISA after 2 weeks

    A repeat ELISA still detects passively acquired maternal antibody.

  • D. CD4 count

    CD4 count stages disease and does not diagnose infection.

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 Dermatology questions

Questions about this Dermatology question

What is the answer to this Dermatology question?

The best answer is B, HIV DNA PCR (nucleic acid test). Maternal IgG crosses the placenta and can persist up to 18 months, so antibody tests are unreliable in exposed infants.

Why is "Western blot" not the answer?

A Western blot also detects maternal antibody.

Why is "Repeat ELISA after 2 weeks" not the answer?

A repeat ELISA still detects passively acquired maternal antibody.

Why is "CD4 count" not the answer?

CD4 count stages disease and does not diagnose infection.

What concept does this question test?

It tests STI: HIV diagnosis in an exposed infant in Dermatology. Virological testing by DNA PCR or other nucleic acid testing diagnoses infection.

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 STI: HIV diagnosis in an exposed infant?

Learn each condition by its primary lesion, site and signature sign. Then use the flashcards and the other Dermatology 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.