Clinical biochemistry: markers of intravascular haemolysis: 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: markers of intravascular haemolysis

Sample item

Two hours after a mismatched transfusion, a patient has dark urine and jaundice. Which laboratory pattern supports intravascular haemolysis?

ALow haptoglobin with raised LDH and free haemoglobinBLow LDH with a raised reticulocyte count and normal bilirubinCRaised haptoglobin with low LDH and low bilirubinDNormal haptoglobin with raised conjugated bilirubin only

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

The answer and the reasoning

A. Low haptoglobin with raised LDH and free haemoglobin

Free haemoglobin released into plasma binds haptoglobin, and the complex is cleared by the liver, so haptoglobin falls. LDH rises from red cell lysis, and free haemoglobin appears in plasma and urine. Unconjugated bilirubin rises with haem breakdown.

Option by option

A. Low haptoglobin with raised LDH and free haemoglobin (correct)
Correct. Consumed haptoglobin with raised LDH and free haemoglobin marks intravascular lysis.
B. Low LDH with a raised reticulocyte count and normal bilirubin
Low LDH is not expected; red cell lysis releases LDH.
C. Raised haptoglobin with low LDH and low bilirubin
Raised haptoglobin and low LDH argue against haemolysis.
D. Normal haptoglobin with raised conjugated bilirubin only
Isolated conjugated hyperbilirubinaemia suggests cholestasis, not haemolysis.

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 Biochemistry question

What is the answer to this Biochemistry question?

The best answer is A, Low haptoglobin with raised LDH and free haemoglobin. Free haemoglobin released into plasma binds haptoglobin, and the complex is cleared by the liver, so haptoglobin falls.

Why is "Low LDH with a raised reticulocyte count and normal bilirubin" not the answer?

Low LDH is not expected; red cell lysis releases LDH.

Why is "Raised haptoglobin with low LDH and low bilirubin" not the answer?

Raised haptoglobin and low LDH argue against haemolysis.

Why is "Normal haptoglobin with raised conjugated bilirubin only" not the answer?

Isolated conjugated hyperbilirubinaemia suggests cholestasis, not haemolysis.

What concept does this question test?

It tests Clinical biochemistry: markers of intravascular haemolysis in Biochemistry. LDH rises from red cell lysis, and free haemoglobin appears in plasma and urine. Unconjugated bilirubin rises with haem breakdown.

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 Clinical biochemistry: markers of intravascular haemolysis?

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.