An assay should be considered to have reached the highest point on the scale at which it meets all criteria. Note that the place on the validation scale is location-specific, such that if an assay is to be used in a different region from the one where it was validated, additional field trials will need to be carried out in the new region to ensure the same level of performance is achieved. If additional closely related species are present in the new region then some additional specificity testing will also need to be carried out.