Define positive predictive value and negative predictive value.

Define positive predictive value and negative predictive value.

• A. PPV is the probability that someone with a positive test actually has the disease; NPV is the probability that someone with a negative test is disease-free.
• B. PPV is the probability that someone with a positive test is disease-free; NPV is the probability that someone with a negative test has the disease.
• C. PPV and NPV are independent of disease prevalence.
• D. PPV equals NPV in all tests.

Answer: (A)