Paediatric infections: dengue early diagnosis: practice question

A Pediatrics 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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Pediatrics · Paediatric infections: dengue early diagnosis

Sample item

During the monsoon, a 7-year-old on the second day of fever has myalgia, retro-orbital pain and a positive tourniquet test. Which laboratory test best confirms dengue at this stage?

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

The answer and the reasoning

D. NS1 antigen detection

NS1 antigen is detectable from the first day of illness up to about day 5, and PCR can also be used in this early phase. IgM antibodies usually appear after about day 5. IgG indicates past or secondary infection, and platelet count is non-specific.

Option by option

  • A. Dengue IgG antibody ELISA

    IgG reflects past exposure or secondary infection and does not confirm acute disease.

  • B. Dengue IgM antibody ELISA

    IgM usually becomes positive only after about 5 days of illness.

  • C. Platelet count

    Thrombocytopenia occurs in several illnesses and cannot confirm dengue.

  • D. NS1 antigen detection (correct)

    Correct. NS1 antigen is positive in the early febrile phase.

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.

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Questions about this Pediatrics question

What is the answer to this Pediatrics question?

The best answer is D, NS1 antigen detection. NS1 antigen is detectable from the first day of illness up to about day 5, and PCR can also be used in this early phase.

Why is "Dengue IgG antibody ELISA" not the answer?

IgG reflects past exposure or secondary infection and does not confirm acute disease.

Why is "Dengue IgM antibody ELISA" not the answer?

IgM usually becomes positive only after about 5 days of illness.

Why is "Platelet count" not the answer?

Thrombocytopenia occurs in several illnesses and cannot confirm dengue.

What concept does this question test?

It tests Paediatric infections: dengue early diagnosis in Pediatrics. IgM antibodies usually appear after about day 5. IgG indicates past or secondary infection, and platelet count is non-specific.

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 Paediatric infections: dengue early diagnosis?

Memorise milestones and the vaccine schedule as tables and revise them often. Then use the flashcards and the other Pediatrics 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.