This document describes the broth microdilution reference method for determining minimum inhibitory concentrations (MICs) of antimicrobial agents, providing a standardized approach for assessing bacterial susceptibility. While clinical interpretation of MIC values is beyond its scope, it supports the categorization of bacteria as susceptible (S), intermediate (I), or resistant (R) and includes necessary method modifications for certain drug-bacteria combinations. It also serves as a benchmark for validating other susceptibility testing methods, such as disc diffusion or diagnostic test devices, to ensure reliable and comparable results.