scope:

This guideline provides protocols for the evaluation of qualitative test performance characteristics. In this document, a qualitative test is restricted to those tests that have only two possible outcomes (eg, positive/negative, present/absent, reactive/nonreactive). EP12 is written primarily for individuals and laboratories that use and evaluate such tests. These protocols are intended to help users determine test performance in their own testing environment. This guideline for qualitative test performance evaluation should help the device developer and the user to meet documentation and regulatory goals. While this document is not intended for manufacturers to establish test performance characteristics, the data analysis principles described here can be used by manufacturers.

Test methods with values that are reported as, for instance, negative, +1, +2, or +3, or as endpoint dilutions (commonly in multiples of 8, reflecting the microtiter plate format, or in multiples of 10) are often called semiquantitative. These methods are not further discussed in EP12, although if one of the values results is considered the cutoff for a positive test, the evaluation protocol recommended here could be applied to that cutoff. For instance, if a test for antibodies to the Lyme disease pathogen was reported as positive if the endpoint titer was ≥ 1:160, the precision and method comparison experiments discussed below could be applied to that cutoff.