Therapeutic drug monitoring and LC–MS/MS

LC–MS/MS is an increasingly important tool in therapeutic drug monitoring as it offers increased sensitivity and specificity compared to other methods, and may be the only viable method for quantifying drugs without natural chromophores or fluorophores. The choice of sample preparation method, column technology, internal standard and mass spectrometric conditions is important to ensure accurate drug measurement and to avoid interference from matrix effects and drug metabolites. LC–MS/MS is a more involved technique than automated immunoassays, but technological advances such as the development of pipetting robots and online solid phase extraction mean that LC–MS/MS is becoming an attractive and convenient method for therapeutic drug monitoring in clinical laboratories.