Immunology: serological tests: 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 · Immunology: serological tests

Sample item

A fourth-generation HIV ELISA can detect infection earlier than third-generation assays because it also detects which viral component?

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

The answer and the reasoning

B. p24 antigen

Fourth-generation assays combine antibody detection with p24 capsid antigen detection, shortening the window period. Third-generation tests detect IgM and IgG antibody only.

Option by option

  • A. Viral envelope lipid

    Envelope lipids are host derived and not used as a target.

  • B. p24 antigen (correct)

    Correct. p24 antigen appears before antibodies.

  • C. Integrase enzyme

    Integrase is not a screening target.

  • D. gp41 antibody only

    Antibody-only detection is the third-generation principle.

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 B, p24 antigen. Fourth-generation assays combine antibody detection with p24 capsid antigen detection, shortening the window period.

Why is "Viral envelope lipid" not the answer?

Envelope lipids are host derived and not used as a target.

Why is "Integrase enzyme" not the answer?

Integrase is not a screening target.

Why is "gp41 antibody only" not the answer?

Antibody-only detection is the third-generation principle.

What concept does this question test?

It tests Immunology: serological tests in Microbiology. Third-generation tests detect IgM and IgG antibody only.

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 Immunology: serological tests?

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.