Leprosy: lepromin test: 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.

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Dermatology · Leprosy: lepromin test

Sample item

Which statement about the lepromin (Mitsuda) test is correct?

AIt is positive in lepromatous leprosyBIt is read at 21 days and is useful for prognosis and classification, not diagnosisCIt detects antibodies to M. lepraeDIt is read at 48 hours and diagnoses leprosy

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

The answer and the reasoning

B. It is read at 21 days and is useful for prognosis and classification, not diagnosis

Lepromin is heat-killed bacilli injected intradermally, and the delayed Mitsuda reaction at 3 to 4 weeks shows cell-mediated immunity. It is positive in tuberculoid disease and negative in lepromatous disease, and is not a diagnostic test as healthy people can be positive.

Option by option

A. It is positive in lepromatous leprosy
The test is negative in lepromatous disease because of specific anergy.
B. It is read at 21 days and is useful for prognosis and classification, not diagnosis (correct)
Correct. The late reaction reflects cell-mediated immunity and has prognostic value.
C. It detects antibodies to M. leprae
It is a delayed skin test, not a serological test.
D. It is read at 48 hours and diagnoses leprosy
The 48 hour Fernandez reaction is early and is not the Mitsuda reaction, and it is not diagnostic.

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 Dermatology question

What is the answer to this Dermatology question?

The best answer is B, It is read at 21 days and is useful for prognosis and classification, not diagnosis. Lepromin is heat-killed bacilli injected intradermally, and the delayed Mitsuda reaction at 3 to 4 weeks shows cell-mediated immunity.

Why is "It is positive in lepromatous leprosy" not the answer?

The test is negative in lepromatous disease because of specific anergy.

Why is "It detects antibodies to M. leprae" not the answer?

It is a delayed skin test, not a serological test.

Why is "It is read at 48 hours and diagnoses leprosy" not the answer?

The 48 hour Fernandez reaction is early and is not the Mitsuda reaction, and it is not diagnostic.

What concept does this question test?

It tests Leprosy: lepromin test in Dermatology. It is positive in tuberculoid disease and negative in lepromatous disease, and is not a diagnostic test as healthy people can be positive.

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 Leprosy: lepromin test?

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.