21 C.F.R. § 866.2850 – Automated zone reader.

(a) Identification. An automated zone reader is a mechanical device intended for medical purposes to measure zone diameters of microbial growth inhibition (or exhibition), such as those observed on the surface of certain culture media used in disc-agar diffusion antimicrobial susceptibility tests. The device aids in decisionmaking respecting the treatment of disease.
(b) Classification. Class I (general controls).