MIC-based dose adjustment: facts and fables

J Antimicrob Chemother. 2018 Mar 1;73(3):564-568. doi: 10.1093/jac/dkx427.


Over recent decades, several publications have described optimization procedures for antibiotic therapy in the individual patient based on antimicrobial MIC values. Most methods include therapeutic drug monitoring and use a single MIC determination plus the relevant pharmacokinetics/pharmacodynamics to adjust the dose to optimize antimicrobial drug exposure and antibacterial effects. However, the use of an MIC obtained by a single MIC determination is inappropriate. First, routine clinical laboratories cannot determine MICs with sufficient accuracy to guide dosage owing to the inherent assay variation in the MIC test. Second, the variation in any MIC determination, whatever method is used, must be accounted for. If dose adjustments are made based on therapeutic drug monitoring and include MIC determinations, MIC variation must be considered to prevent potential underdosing of patients. We present the problems and some approaches that could be used in clinical practice.

MeSH terms

  • Anti-Bacterial Agents / administration & dosage*
  • Anti-Bacterial Agents / pharmacokinetics
  • Bacteria / drug effects
  • Biological Variation, Population
  • Dose-Response Relationship, Drug
  • Drug Monitoring
  • Humans
  • Microbial Sensitivity Tests / methods
  • Microbial Sensitivity Tests / standards*
  • Reproducibility of Results


  • Anti-Bacterial Agents