Assay performance - Assay procedures must be standardized. Any deviation from the standardized method must be recorded and justified by re-validation of the method. Such changes in procedure must be documented in the report. Optimal performance is more easily obtained using automated staining platforms, rather than manual methods. Personnel performing assays must have their competency assessed at regular intervals.
Assay controls - Standardized control materials, either purchased products or conforming to defined manufacturing standards (eg, cell lines defined by the laboratory director, must be consistently used by each laboratory with each run of tests).
Adequate control materials include cell lines or tumor blocks with well-defined negative, equivocal, and positive expression and gene amplification assay results. If controls do not show usual results, assay must be repeated rather than interpreted.