Haematology: multiple myeloma: practice question

A General Medicine 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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General Medicine · Haematology: multiple myeloma

Sample item

A 66-year-old man has back pain and fatigue. Creatinine is 2.4 mg/dL, calcium 12 mg/dL, haemoglobin 8.4 g/dL and ESR 120 mm in the first hour. Urine dipstick is negative for protein, yet the sulfosalicylic acid test is strongly positive. What explains this discrepancy?

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

The answer and the reasoning

D. Excretion of free monoclonal light chains, which dipsticks do not detect

Urine dipsticks are mainly sensitive to albumin, while sulfosalicylic acid precipitates all proteins including free light chains (Bence Jones protein). A negative dipstick with a positive acid test, together with anaemia, renal failure, hypercalcaemia and bone pain, suggests multiple myeloma. Serum protein electrophoresis with immunofixation and serum free light chains confirm it.

Option by option

  • A. A false positive from penicillin in the urine

    Penicillin and contrast cause false-positive acid tests, but cannot explain the clinical picture.

  • B. Heavy glomerular albuminuria from membranous nephropathy

    Heavy albuminuria would make the dipstick strongly positive.

  • C. Albuminuria below the sensitivity of the dipstick

    Low-grade albuminuria would not give a strongly positive acid test.

  • D. Excretion of free monoclonal light chains, which dipsticks do not detect (correct)

    Correct. Free light chains are not albumin, so the dipstick misses them but the acid test detects them.

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 General Medicine question

What is the answer to this General Medicine question?

The best answer is D, Excretion of free monoclonal light chains, which dipsticks do not detect. Urine dipsticks are mainly sensitive to albumin, while sulfosalicylic acid precipitates all proteins including free light chains (Bence Jones protein).

Why is "A false positive from penicillin in the urine" not the answer?

Penicillin and contrast cause false-positive acid tests, but cannot explain the clinical picture.

Why is "Heavy glomerular albuminuria from membranous nephropathy" not the answer?

Heavy albuminuria would make the dipstick strongly positive.

Why is "Albuminuria below the sensitivity of the dipstick" not the answer?

Low-grade albuminuria would not give a strongly positive acid test.

What concept does this question test?

It tests Haematology: multiple myeloma in General Medicine. A negative dipstick with a positive acid test, together with anaemia, renal failure, hypercalcaemia and bone pain, suggests multiple myeloma. Serum protein electrophoresis with immunofixation and serum free light chains confirm it.

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 Haematology: multiple myeloma?

For each disease know the classic presentation, the best test, and the first-line treatment. Then use the flashcards and the other General Medicine 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.