Given below are two statements:Statement I: Validity expresses the ability of a test to separate or distinguish those who have the disease from those who do not.Statement II: Sensitivity refers to the ability of a test to identify correctly all those who have the disease.Choose the correct answer:

1. A

   Statement I is correct but Statement II is incorrect

2. B

   Both Statement I and Statement II are incorrect

3. C

   Both Statement I and Statement II are correct

4. D

   Statement I is incorrect but Statement II is correct

Appeared in: BHU NO - 12 April 2024

Explanation

• Statement I is correct. Validity is the fundamental ability of a test to accurately distinguish between individuals with a disease and those without it.
• Statement II is also correct. Sensitivity is a specific measure of validity that quantifies the proportion of actual cases (true positives) that are correctly identified by the test.
• Both concepts are essential for evaluating the performance and utility of any screening or diagnostic tool in a clinical setting.

Why Other Options Were Wrong

• Option A: This option is incorrect because Statement II, which defines sensitivity, is also a correct and standard definition in epidemiology.
• Option B: This option is incorrect because both statements provide accurate definitions for validity and sensitivity, respectively.
• Option D: This option is incorrect because Statement I provides a correct definition of validity.

Related Visual

Clinical Relevance

• Nursing practice connection: Knowing Principles of Diagnostic Test Evaluation helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
• Nurses must understand sensitivity and specificity to interpret screening results, make appropriate clinical decisions, and provide accurate patient education.
• A high-sensitivity test (e.g., a rapid antigen test for COVID-19) is used for initial screening to catch as many potential cases as possible, minimizing the risk of missing an infection.
• A high-specificity test (e.g., an RT-PCR test for COVID-19) is used to confirm a diagnosis, ensuring that a positive result is truly indicative of the disease, which prevents unnecessary treatment or quarantine.

How to Approach the Question

• First, read Statement I carefully and assess its accuracy. Recall the definition of 'validity' in the context of diagnostic tests. It refers to the test's overall accuracy in distinguishing between diseased and non-diseased groups.
• Next, read Statement II and assess its accuracy. Recall the definition of 'sensitivity'. It refers to the test's ability to correctly identify those who have the disease (true positives).
• Determine if each statement is correct or incorrect based on standard epidemiological definitions.
• Compare your assessment of both statements with the four given options.
• Select the option that accurately describes the correctness of both Statement I and Statement II.

Concept Tested & Keywords

• Concept Tested: Principles of Diagnostic Test Evaluation
• Stem keywords: Validity, Sensitivity, Statement I, Statement II, diagnostic test
• Lead-in keywords: Choose the correct answer

Question ID

QOqtZvgykALTuaDo_-mB_v

Copy ID

Reference Book

E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart A (pp 26-201 of 604) p. 139-141