Hypersensitivity: type I: practice question

A Pathology 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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Pathology · Hypersensitivity: type I

Sample item

A 34-year-old woman develops urticaria, wheeze and hypotension 10 minutes after a wasp sting and recovers after treatment. Which blood test drawn within a few hours best supports mast cell degranulation as the cause?

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

The answer and the reasoning

D. Serum tryptase

Anaphylaxis is an IgE-mediated type I reaction. Mast cells release tryptase, which peaks 1 to 2 hours after onset and stays raised for several hours, so a sample then retrospectively confirms the event. Complement levels are not the usual marker of type I reactions.

Option by option

  • A. Erythrocyte sedimentation rate

    ESR is a non-specific inflammatory marker that does not confirm mast cell degranulation.

  • B. Total serum IgG

    Total IgG does not reflect an acute IgE-mediated mast cell event.

  • C. Serum C3 and C4

    Complement levels are used in immune complex diseases and hereditary angioedema, not to confirm anaphylaxis.

  • D. Serum tryptase (correct)

    Correct. Tryptase is released with histamine from mast cell granules and persists longer than histamine.

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 Pathology question

What is the answer to this Pathology question?

The best answer is D, Serum tryptase. Anaphylaxis is an IgE-mediated type I reaction.

Why is "Erythrocyte sedimentation rate" not the answer?

ESR is a non-specific inflammatory marker that does not confirm mast cell degranulation.

Why is "Total serum IgG" not the answer?

Total IgG does not reflect an acute IgE-mediated mast cell event.

Why is "Serum C3 and C4" not the answer?

Complement levels are used in immune complex diseases and hereditary angioedema, not to confirm anaphylaxis.

What concept does this question test?

It tests Hypersensitivity: type I in Pathology. Mast cells release tryptase, which peaks 1 to 2 hours after onset and stays raised for several hours, so a sample then retrospectively confirms the event. Complement levels are not the usual marker of type I reactions.

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 Hypersensitivity: type I?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology 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.