The prevalence of a condition significantly impacts the NPV of a test. In populations where the condition is rare, the NPV tends to be higher because there are fewer false negatives relative to true negatives. Conversely, in populations with high prevalence, the NPV decreases, as the likelihood of false negatives increases.
This dependency on prevalence means that toxicologists must consider the population being tested when interpreting NPV. A test with high NPV in one setting might not perform as well in another with different prevalence rates.
