What statistic best indicates the false negative rate of a diagnostic test?

• A. Sensitivity
• B. Specificity
• C. Positive Predictive Value
• D. Negative Predictive Value

Answer: (A)

False negative rate is the proportion of people who have the disease but test negative. Sensitivity captures the test’s ability to detect disease among those who truly have it, defined as true positives divided by all people with the disease. Since FN rate equals 1 minus sensitivity, a test with higher sensitivity has fewer false negatives. That’s why sensitivity best indicates how often the test misses disease. Specificity relates to correctly identifying those without disease, while predictive values relate to the probability that a test result reflects reality given the test result and disease prevalence, not the rate of missed disease among the diseased.