Respiratory medicine: tuberculosis diagnosis: practice question

A General Medicine 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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General Medicine · Respiratory medicine: tuberculosis diagnosis

Sample item

A 35-year-old man attending a district clinic in India has had cough for 3 weeks with evening fever and weight loss. Under the National TB Elimination Programme, which test is recommended as the initial diagnostic test for presumptive pulmonary tuberculosis?

AA nucleic acid amplification test such as CBNAAT or TruenatBMantoux tuberculin skin testCSputum smear microscopy aloneDChest radiograph alone, treating on the basis of the film

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

The answer and the reasoning

A. A nucleic acid amplification test such as CBNAAT or Truenat

NTEP recommends a WHO-approved molecular test (NAAT) as the initial test for all presumptive TB, because it is more sensitive than smear microscopy and detects rifampicin resistance at the same time, allowing drug susceptibility-guided treatment from the start. Smear, culture and radiography serve as supportive or follow-up tests.

Option by option

A. A nucleic acid amplification test such as CBNAAT or Truenat (correct)
Correct. A molecular test confirms Mycobacterium tuberculosis and screens for rifampicin resistance in one step.
B. Mantoux tuberculin skin test
The Mantoux test shows infection, not disease, and is positive in many healthy BCG-vaccinated or exposed Indians.
C. Sputum smear microscopy alone
Smear microscopy misses many cases because it needs a high bacillary load and gives no resistance information.
D. Chest radiograph alone, treating on the basis of the film
A radiograph is not specific and should not alone be used to start therapy when microbiological testing is possible.

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.

Questions about this General Medicine question

What is the answer to this General Medicine question?

The best answer is A, A nucleic acid amplification test such as CBNAAT or Truenat. NTEP recommends a WHO-approved molecular test (NAAT) as the initial test for all presumptive TB, because it is more sensitive than smear microscopy and detects rifampicin resistance at the same time, allowing drug susceptibility-guided treatment from the start.

Why is "Mantoux tuberculin skin test" not the answer?

The Mantoux test shows infection, not disease, and is positive in many healthy BCG-vaccinated or exposed Indians.

Why is "Sputum smear microscopy alone" not the answer?

Smear microscopy misses many cases because it needs a high bacillary load and gives no resistance information.

Why is "Chest radiograph alone, treating on the basis of the film" not the answer?

A radiograph is not specific and should not alone be used to start therapy when microbiological testing is possible.

What concept does this question test?

It tests Respiratory medicine: tuberculosis diagnosis in General Medicine. Smear, culture and radiography serve as supportive or follow-up tests.

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 Respiratory medicine: tuberculosis diagnosis?

For each disease know the classic presentation, the best test, and the first-line treatment. Then use the flashcards and the other General Medicine 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.