Antimicrobial Susceptibility Testing Systems

<jats:title>Abstract</jats:title> <jats:p>Antimicrobial susceptibility testing (AST) of clinically significant bacterial isolates is one of the most important functions performed by clinical microbiology laboratories. This chapter contains updated information on differences in the pathways for new and revised breakpoint clearance in the United States and the European Union; a summary of current regulations, available validation guidance documents, and differences in the approaches of the two groups; and how each draws its conclusions. Newer systems such as Q‐Linea ASTar, Selux NGP, bioMérieux Reveal, Affinity Biosensors LifeScale, and Accelerate Pheno, as well as other marketed (FDA and CE marked) and investigational AST systems, are discussed, as well as technical challenges that can affect AST system performance.</jats:p>