National health programmes: slide positivity rate: 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 · National health programmes: slide positivity rate

Sample item

In a malaria-endemic block with a population of 50,000, 5,000 blood slides were examined in a year and 250 were positive. What is the slide positivity rate?

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

The answer and the reasoning

B. 5 percent

The slide positivity rate is positive slides divided by slides examined, times 100, so 250 divided by 5,000 is 5 percent. The annual blood examination rate is slides examined per 100 population (10 percent), and the annual parasite incidence is 5 per 1,000 population.

Option by option

  • A. 10 percent

    This is the annual blood examination rate, slides per 100 population.

  • B. 5 percent (correct)

    Correct. 250 positive of 5,000 examined slides is 5 percent.

  • C. 20 percent

    This is an arithmetic error that matches no malaria indicator.

  • D. 0.5 percent

    This is the annual parasite incidence expressed as a percentage of the population.

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 PSM question

What is the answer to this PSM question?

The best answer is B, 5 percent. The slide positivity rate is positive slides divided by slides examined, times 100, so 250 divided by 5,000 is 5 percent.

Why is "10 percent" not the answer?

This is the annual blood examination rate, slides per 100 population.

Why is "20 percent" not the answer?

This is an arithmetic error that matches no malaria indicator.

Why is "0.5 percent" not the answer?

This is the annual parasite incidence expressed as a percentage of the population.

What concept does this question test?

It tests National health programmes: slide positivity rate in PSM. The annual blood examination rate is slides examined per 100 population (10 percent), and the annual parasite incidence is 5 per 1,000 population.

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 National health programmes: slide positivity rate?

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.