Antimicrobial susceptibility test (AST) results are commonly used in practice to help guide antimicrobial therapy. AST results are reported qualitatively (S/I/R) and quantitatively, more commonly expressed as MIC (minimum inhibitory concentration). This webinar explains MICs, what is a clinical breakpoint, how the numbers are obtained and how to interpret these using examples from IDEXX reports. It also discusses why you might not receive an MIC result for every antimicrobial-organism-site combination, limitations of clinical breakpoints and limitations with interpreting these results. The choice of antimicrobial should not be based on the MIC at face value, but should also consider how that value relates to clinical breakpoint, site of infection, patient factors, etc. Difficult cases may still require a discussion with the microbiology lab and specialists, repeat sample testing and expanded antimicrobial testing. This webinar is provided by BSAVA Education Partner IDEXX. A collection of IDEXX ‘topic of the month’ webinars is available here.