Keywords: Diagnostic tests, Gray Zone
CBER regulates two types of In Vitro Diagnostic (IVD) devices for infectious diseases: blood donor screening and diagnostics. In general, Gray Zone (GZ) is only used in investigational stage to potentially adjust the cutoff value but omitted in the final output for donor screening assays, while it is used in both investigation and real practice for diagnostic assays. The reasons will be provided in this talk. In addition, the potential bias of only utilizing GZ in investigation but not in real practice will be explored and compared for these two types of devices.