Screening: practice question

A PSM 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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PSM · Screening

Sample item

The same screening test, with unchanged sensitivity and specificity, is applied in two populations, one with a higher disease prevalence. Which change is expected in the higher prevalence population?

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

The answer and the reasoning

B. A higher positive predictive value

Sensitivity and specificity are properties of the test and do not change with prevalence. Predictive values depend on prevalence: as prevalence rises, positive predictive value increases and negative predictive value falls.

Option by option

  • A. A higher negative predictive value

    Negative predictive value falls, not rises, as prevalence increases.

  • B. A higher positive predictive value (correct)

    Correct. More true positives relative to false positives raises the positive predictive value.

  • C. A lower specificity

    Specificity is also an intrinsic property of the test and stays constant.

  • D. A higher sensitivity

    Sensitivity is intrinsic to the test and does not vary with prevalence.

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.

More PSM questions

Questions about this PSM question

What is the answer to this PSM question?

The best answer is B, A higher positive predictive value. Sensitivity and specificity are properties of the test and do not change with prevalence.

Why is "A higher negative predictive value" not the answer?

Negative predictive value falls, not rises, as prevalence increases.

Why is "A lower specificity" not the answer?

Specificity is also an intrinsic property of the test and stays constant.

Why is "A higher sensitivity" not the answer?

Sensitivity is intrinsic to the test and does not vary with prevalence.

What concept does this question test?

It tests Screening in PSM. Predictive values depend on prevalence: as prevalence rises, positive predictive value increases and negative predictive value falls.

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 Screening?

Practise biostatistics with small calculations until sensitivity, predictive values and risk measures are automatic. Then use the flashcards and the other PSM 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.