false-negative ratio

false-negative ratio

,

FNR

The ratio of subjects affected by an illness whose test results wrongly suggest they are disease-free to all those subjects who have the disease. The false-negative ratio of a test is useful in determining the test's reliability (i.e., the higher the ratio, the less reliable the test).

A high FNR may be biological or analytical in origin. Biological false-negative test results may occur when a test is performed at the wrong stage of an illness (e.g., before an antibody or antigen is found in the blood). Analytical false negatives may result when a test lacks adequate sensitivity or specificity to detect an agent that is already present.