This standard establishes acceptable performance criteria for antimicrobial susceptibility test (AST) devices that are used for determining minimal inhibitory concentrations (MIC) and/or interpretive category determinations (Susceptible, Intermediate, Resistant, SIR) of bacteria to antimicrobial agents in medical laboratories. This standard specifies requirements for AST devices (including diffusion test systems), and procedures for assessing performance of such devices. It defines how a performance evaluation of an AST device should be conducted. This standard has been developed to guide manufacturers in the conduct of performance evaluation studies.