Renal: creatinine clearance: 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 · Renal: creatinine clearance

Sample item

A patient has plasma creatinine 1 mg/dL, urine creatinine 60 mg/dL and urine flow 2 mL/min. What is the creatinine clearance?

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

The answer and the reasoning

C. 120 mL/min

Clearance = urine concentration multiplied by urine flow divided by plasma concentration. Here 60 x 2 / 1 = 120 mL/min. Creatinine is freely filtered and slightly secreted, so its clearance approximates, and slightly overestimates, the glomerular filtration rate.

Option by option

  • A. 240 mL/min

    This doubles the correct result and has no arithmetic basis.

  • B. 60 mL/min

    This ignores the urine flow term; 60/1 gives 60.

  • C. 120 mL/min (correct)

    Correct. 60 x 2 / 1 = 120 mL/min.

  • D. 30 mL/min

    This results from dividing by 2 instead of multiplying.

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 Physiology question

What is the answer to this Physiology question?

The best answer is C, 120 mL/min. Clearance = urine concentration multiplied by urine flow divided by plasma concentration.

Why is "240 mL/min" not the answer?

This doubles the correct result and has no arithmetic basis.

Why is "60 mL/min" not the answer?

This ignores the urine flow term; 60/1 gives 60.

Why is "30 mL/min" not the answer?

This results from dividing by 2 instead of multiplying.

What concept does this question test?

It tests Renal: creatinine clearance in Physiology. Here 60 x 2 / 1 = 120 mL/min. Creatinine is freely filtered and slightly secreted, so its clearance approximates, and slightly overestimates, the glomerular filtration rate.

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 Renal: creatinine clearance?

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.