Virology: Tzanck smear: 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.

Try it

Microbiology · Virology: Tzanck smear

Sample item

A scraping from the base of a vesicle stained by Giemsa shows multinucleated giant cells with intranuclear inclusions. How should this result be interpreted?

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

The answer and the reasoning

A. Consistent with herpes simplex or varicella-zoster infection, and confirmed by PCR or antigen detection

The Tzanck smear shows cytopathic change from herpesviruses, with ballooned, multinucleated cells with intranuclear inclusions. Herpes simplex and varicella-zoster look identical, and the test is relatively insensitive, so PCR or direct fluorescent antibody testing is needed to identify the virus. PCR of vesicle fluid is the preferred test.

Option by option

  • A. Consistent with herpes simplex or varicella-zoster infection, and confirmed by PCR or antigen detection (correct)

    Correct. The smear shows herpesvirus change but cannot name the virus.

  • B. Specific for herpes simplex virus type 2

    The smear cannot distinguish type 2 from type 1 herpes simplex virus.

  • C. Diagnostic of smallpox

    Smallpox is an orthopoxvirus with cytoplasmic inclusions and does not show this change.

  • D. Specific for varicella and excludes herpes simplex

    Varicella-zoster and herpes simplex give identical cytology, so herpes simplex is not excluded.

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 A, Consistent with herpes simplex or varicella-zoster infection, and confirmed by PCR or antigen detection. The Tzanck smear shows cytopathic change from herpesviruses, with ballooned, multinucleated cells with intranuclear inclusions.

Why is "Specific for herpes simplex virus type 2" not the answer?

The smear cannot distinguish type 2 from type 1 herpes simplex virus.

Why is "Diagnostic of smallpox" not the answer?

Smallpox is an orthopoxvirus with cytoplasmic inclusions and does not show this change.

Why is "Specific for varicella and excludes herpes simplex" not the answer?

Varicella-zoster and herpes simplex give identical cytology, so herpes simplex is not excluded.

What concept does this question test?

It tests Virology: Tzanck smear in Microbiology. Herpes simplex and varicella-zoster look identical, and the test is relatively insensitive, so PCR or direct fluorescent antibody testing is needed to identify the virus. PCR of vesicle fluid is the preferred test.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Virology: Tzanck smear?

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.