Haematology: polycythaemia vera: 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 · Haematology: polycythaemia vera

Sample item

A 58-year-old man has headache, itching after a hot bath and a plethoric face. Haemoglobin is 19 g/dL, platelets 480,000 and leukocytes 13,000 per microlitre, with splenomegaly. Which finding supports polycythaemia vera and not secondary polycythaemia?

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

The answer and the reasoning

B. Low serum erythropoietin level with JAK2 V617F mutation

Polycythaemia vera is a myeloproliferative neoplasm, with a JAK2 V617F mutation in most patients, that causes erythropoietin-independent red cell production, so serum erythropoietin is low. Secondary polycythaemia has raised erythropoietin, whether from hypoxia or from a tumour. Treatment is by phlebotomy to keep the haematocrit below 45 percent with low-dose aspirin, and complications include thrombosis and Budd-Chiari syndrome.

Option by option

  • A. Raised carboxyhaemoglobin level

    Raised carboxyhaemoglobin in smokers causes secondary polycythaemia through tissue hypoxia.

  • B. Low serum erythropoietin level with JAK2 V617F mutation (correct)

    Correct. Low erythropoietin with JAK2 mutation indicates autonomous red cell production.

  • C. Reduced arterial oxygen saturation

    Reduced arterial oxygen saturation drives secondary polycythaemia, as in chronic lung disease or high altitude.

  • D. High serum erythropoietin level

    A high erythropoietin level is expected in secondary polycythaemia.

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 B, Low serum erythropoietin level with JAK2 V617F mutation. Polycythaemia vera is a myeloproliferative neoplasm, with a JAK2 V617F mutation in most patients, that causes erythropoietin-independent red cell production, so serum erythropoietin is low.

Why is "Raised carboxyhaemoglobin level" not the answer?

Raised carboxyhaemoglobin in smokers causes secondary polycythaemia through tissue hypoxia.

Why is "Reduced arterial oxygen saturation" not the answer?

Reduced arterial oxygen saturation drives secondary polycythaemia, as in chronic lung disease or high altitude.

Why is "High serum erythropoietin level" not the answer?

A high erythropoietin level is expected in secondary polycythaemia.

What concept does this question test?

It tests Haematology: polycythaemia vera in Pathology. Secondary polycythaemia has raised erythropoietin, whether from hypoxia or from a tumour. Treatment is by phlebotomy to keep the haematocrit below 45 percent with low-dose aspirin, and complications include thrombosis and Budd-Chiari syndrome.

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 Haematology: polycythaemia vera?

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.