Overall Conclusions on Bioanalytical Screening Assays

6 GENERAL CONSIDERATIONS CONCERNING THE PERFORMANCE CRITERIA FOR SCREENING ASSAYS 

When choosing to implement a particular screening assay for antibiotic residue analysis, the laboratory must ensure that the performance criterion is fit for the intended purpose and in line with the appropriate legislative requirements within that country or the country for which the testing is undertaken, for example, the country to which the produce is to be exported. 

Two statistical limits (CCa and CCfi) have been established for determination of the concentrations above which a method reliably distinguishes and quantifies residues, on the basis of method variability and the risk of an incorrect decision. The decision limit (CCa) is the concentration of a residue in a sample at which it is decided that the sample is non-compliant with a pre-defined statistical certainty (a 

A key performance factor for the evaluation of a screening method is demonstration that the chosen STC can be achieved. The STC should be low enough to provide confidence that the antibiotic residue can be detected at the appropriate RL in the sample, that is, that there is sufficient margin of difference between the STC and the RL. This implies that the CCP is equal to or less than the RL. It does not necessarily require an estimation of the numeric value of CCP depending on the capability of the screening assay. 

Schwarz S, Chaslus-Dancla E, Use of antimicrobials in veterinary medicine and mechanisms of resistance, Vet. Res. 2001 32 201-225. 

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