Immunisation: shake test: 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 · Immunisation: shake test

Sample item

A health worker suspects that a vial of DPT vaccine has been frozen. Which test is used to check for freeze damage, and what indicates damage?

AMantoux testBShake test; a suspect vial sediments at the same rate as or faster than a control frozen vialCVaccine vial monitor colour change onlyDLitmus test

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

The answer and the reasoning

B. Shake test; a suspect vial sediments at the same rate as or faster than a control frozen vial

In the shake test a suspect vial is compared with a deliberately frozen and thawed control vial of the same batch. If the suspect vial sediments at the same rate or faster than the control, it is freeze-damaged and discarded.

Option by option

A. Mantoux test
Mantoux is a TB skin test.
B. Shake test; a suspect vial sediments at the same rate as or faster than a control frozen vial (correct)
Correct. Comparative sedimentation shows freeze damage.
C. Vaccine vial monitor colour change only
VVM shows heat exposure and not freezing.
D. Litmus test
Litmus does not detect freezing damage.

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 Pediatrics question

What is the answer to this Pediatrics question?

The best answer is B, Shake test; a suspect vial sediments at the same rate as or faster than a control frozen vial. In the shake test a suspect vial is compared with a deliberately frozen and thawed control vial of the same batch.

Why is "Mantoux test" not the answer?

Mantoux is a TB skin test.

Why is "Vaccine vial monitor colour change only" not the answer?

VVM shows heat exposure and not freezing.

Why is "Litmus test" not the answer?

Litmus does not detect freezing damage.

What concept does this question test?

It tests Immunisation: shake test in Pediatrics. If the suspect vial sediments at the same rate or faster than the control, it is freeze-damaged and discarded.

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 Immunisation: shake test?

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.