Clinical biochemistry: secretin test for gastrinoma: practice question

A Biochemistry 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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Biochemistry · Clinical biochemistry: secretin test for gastrinoma

Sample item

A 45-year-old man has recurrent duodenal ulcers and diarrhoea. Fasting gastrin is markedly raised with gastric pH 1.5. After intravenous secretin, serum gastrin rises sharply. What is the diagnosis?

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

The answer and the reasoning

B. Gastrinoma (Zollinger-Ellison syndrome)

High gastrin with a very acid stomach points to autonomous gastrin secretion. Secretin normally inhibits G cells, but gastrinoma cells respond paradoxically, so gastrin rises sharply. Gastrin is also raised in atrophic gastritis, but gastric pH is high there.

Option by option

  • A. Helicobacter pylori duodenal ulcer

    Uncomplicated H. pylori ulcers have only a mildly raised gastrin and no secretin response.

  • B. Gastrinoma (Zollinger-Ellison syndrome) (correct)

    Correct. A paradoxical gastrin rise with secretin and acid hypersecretion indicates a gastrinoma.

  • C. Antral G-cell hyperplasia with exaggerated meal response

    G-cell hyperplasia shows an exaggerated rise after a meal, but no paradoxical rise with secretin.

  • D. Atrophic gastritis with achlorhydria

    Atrophic gastritis causes high gastrin with a high gastric pH.

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 Biochemistry question

What is the answer to this Biochemistry question?

The best answer is B, Gastrinoma (Zollinger-Ellison syndrome). High gastrin with a very acid stomach points to autonomous gastrin secretion.

Why is "Helicobacter pylori duodenal ulcer" not the answer?

Uncomplicated H. pylori ulcers have only a mildly raised gastrin and no secretin response.

Why is "Antral G-cell hyperplasia with exaggerated meal response" not the answer?

G-cell hyperplasia shows an exaggerated rise after a meal, but no paradoxical rise with secretin.

Why is "Atrophic gastritis with achlorhydria" not the answer?

Atrophic gastritis causes high gastrin with a high gastric pH.

What concept does this question test?

It tests Clinical biochemistry: secretin test for gastrinoma in Biochemistry. Secretin normally inhibits G cells, but gastrinoma cells respond paradoxically, so gastrin rises sharply. Gastrin is also raised in atrophic gastritis, but gastric pH is high there.

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 Clinical biochemistry: secretin test for gastrinoma?

Build one table of enzyme deficiency, disease, inheritance and key finding, then revise it by spaced recall. Then use the flashcards and the other Biochemistry 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.