How New Regulation of Laboratory-Developed Antimicrobial Susceptibility Tests Will Affect Infectious Diseases Clinical Practice

Abstract Antimicrobial resistance (AMR) affects 2.8 million Americans annually. AMR is identified through antimicrobial susceptibility testing (AST), but current and proposed regulatory policies from the United States Food and Drug Administration (FDA) jeopardize the future availability of AST for many microorganisms. Devices that perform AST must be cleared by the FDA using their susceptibility test interpretive criteria, also known as breakpoints. The FDA list of breakpoints is relatively short. Today, laboratories supplement FDA breakpoints using breakpoints published by the Clinical and Laboratory Standards Institute, using legacy devices and laboratory-developed tests (LDTs). FDA proposes to regulate LDTs, and with no FDA breakpoints for many drug–bug combinations, the risk is loss of AST for key clinical indications and stifling innovation in technology development. Effective solutions require collaboration between manufacturers, infectious diseases clinicians, pharmacists, laboratories, and the FDA.