Analytical features in qualitative analysis

We present and discuss a systematic approach to properly characterizing both qualitative methods and yes/no binary responses. It is based on careful adaptation of the conventional analytical properties in quantitative analysis; accuracy and precision cannot be applied in this context. Reliability, unreliability, traceability, representativeness, sensitivity, selectivity, robustness and productivity-related properties, as well as their mutual relationships, are dealt with. The main aim is to support the analytical quality of qualitative analysis, which is a substantial part of today's and tomorrow's demands for (bio)chemical information requested by clients of routine analytical laboratories. We also consider in general terms the validation of qualitative (test) methods based on the analytical features used to ensure their fitness for purpose.