title: Before defining performance criteria we must agree on what a "qualitative test procedure" is.
abstract: The term "qualitative test" is ambiguous and should not be used for nominal (classification) or ordinal (grading) tests. Characteristics for nominal and ordinal scale test results, such as traceability and uncertainty, remains to be established before general performance criteria can be agreed upon. For ordinal binary test with a quantitative back ground scale an assay could be characterized with the three quantities "C5", "C50", and "C95". The C50-value, or the equivalence point, ought to be declared by the manufacturers of diagnostic products. For the correct understanding and communication of results from ordinal and nominal tests the way of expressing the results also need to be harmonized.
authors: Gunnar
authors: G
authors: Nordin
mesh_terms: D019411:Clinical Laboratory Techniques / Q000592:standards*; D016001:Confidence Intervals; D011786:Quality Control; D012306:Risk