Vitamins and minerals: biochemical profile of osteomalacia: 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 · Vitamins and minerals: biochemical profile of osteomalacia

Sample item

A 38-year-old woman who wears fully covering clothing and has little sun exposure has diffuse bone pain, proximal muscle weakness and pseudofractures on radiograph. Which biochemical profile is expected?

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

The answer and the reasoning

B. Low calcium, low phosphate, raised PTH, raised alkaline phosphatase

Vitamin D deficiency reduces calcium absorption, so calcium falls and PTH rises. PTH increases renal phosphate loss, so phosphate is low, and osteoblast activity in unmineralised osteoid raises alkaline phosphatase. Pseudofractures (Looser zones) are characteristic.

Option by option

  • A. High calcium, low phosphate, raised PTH, raised alkaline phosphatase

    High calcium with raised PTH points to primary hyperparathyroidism.

  • B. Low calcium, low phosphate, raised PTH, raised alkaline phosphatase (correct)

    Correct. Secondary hyperparathyroidism with phosphate loss and raised ALP is typical.

  • C. Normal calcium, normal phosphate, normal PTH, normal alkaline phosphatase

    Normal values are seen in osteoporosis, where mineralisation is normal.

  • D. Low calcium, high phosphate, raised PTH, normal alkaline phosphatase

    High phosphate with normal ALP suggests chronic kidney disease or hypoparathyroidism patterns.

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, Low calcium, low phosphate, raised PTH, raised alkaline phosphatase. Vitamin D deficiency reduces calcium absorption, so calcium falls and PTH rises.

Why is "High calcium, low phosphate, raised PTH, raised alkaline phosphatase" not the answer?

High calcium with raised PTH points to primary hyperparathyroidism.

Why is "Normal calcium, normal phosphate, normal PTH, normal alkaline phospha…" not the answer?

Normal values are seen in osteoporosis, where mineralisation is normal.

Why is "Low calcium, high phosphate, raised PTH, normal alkaline phosphatase" not the answer?

High phosphate with normal ALP suggests chronic kidney disease or hypoparathyroidism patterns.

What concept does this question test?

It tests Vitamins and minerals: biochemical profile of osteomalacia in Biochemistry. PTH increases renal phosphate loss, so phosphate is low, and osteoblast activity in unmineralised osteoid raises alkaline phosphatase. Pseudofractures (Looser zones) are characteristic.

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 Vitamins and minerals: biochemical profile of osteomalacia?

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.