Blood and immunity: haptoglobin in haemolysis: practice question

A Physiology 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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Physiology · Blood and immunity: haptoglobin in haemolysis

Sample item

A patient with a mechanical aortic valve has anaemia, a raised LDH and free haemoglobin in plasma. What is expected for serum haptoglobin, and why?

AHigh, because haptoglobin is released from lysed red cellsBLow, because haptoglobin-haemoglobin complexes are rapidly cleared by macrophagesCNormal, because it binds only haem released by extravascular haemolysisDHigh, because it is an acute phase protein produced in excess during haemolysis

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

The answer and the reasoning

B. Low, because haptoglobin-haemoglobin complexes are rapidly cleared by macrophages

Haptoglobin binds free plasma haemoglobin released in intravascular haemolysis. The complex is removed quickly by the reticuloendothelial system, so serum haptoglobin falls. Low haptoglobin with raised LDH and free haemoglobin is the characteristic pattern.

Option by option

A. High, because haptoglobin is released from lysed red cells
Haptoglobin is made in the liver, not stored in red cells.
B. Low, because haptoglobin-haemoglobin complexes are rapidly cleared by macrophages (correct)
Correct. Consumption by complex formation and clearance lowers the level.
C. Normal, because it binds only haem released by extravascular haemolysis
It binds free haemoglobin, not haem alone, and is consumed in intravascular haemolysis.
D. High, because it is an acute phase protein produced in excess during haemolysis
Haptoglobin is an acute phase protein, but in haemolysis consumption outweighs synthesis.

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 Physiology question

What is the answer to this Physiology question?

The best answer is B, Low, because haptoglobin-haemoglobin complexes are rapidly cleared by macrophages. Haptoglobin binds free plasma haemoglobin released in intravascular haemolysis.

Why is "High, because haptoglobin is released from lysed red cells" not the answer?

Haptoglobin is made in the liver, not stored in red cells.

Why is "Normal, because it binds only haem released by extravascular haemolys…" not the answer?

It binds free haemoglobin, not haem alone, and is consumed in intravascular haemolysis.

Why is "High, because it is an acute phase protein produced in excess during…" not the answer?

Haptoglobin is an acute phase protein, but in haemolysis consumption outweighs synthesis.

What concept does this question test?

It tests Blood and immunity: haptoglobin in haemolysis in Physiology. The complex is removed quickly by the reticuloendothelial system, so serum haptoglobin falls. Low haptoglobin with raised LDH and free haemoglobin is the characteristic pattern.

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 Blood and immunity: haptoglobin in haemolysis?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology 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.