Fig. 2

The path to clinical implementation of a targeted LC–MS/MS assay. Targeted LC–MS/MS assays for tumor markers may be developed following identification and verification of novel tumors markers in the research setting, alternatively they may be developed for established markers due to limitations or lack of alternative methodologies (Panel 1). This path may not be as linear as shown due to challenges that may be encountered at the various stages necessitating a return to the method optimization stage, method validation, or updates in post-implementation monitoring protocols. ^aDenote analytical performance metrics that require validation for laboratory-developed tests as per the College of American Pathologists. ^bPrior to investing significant resources in a method validation, pre-validation evaluation may be performed to assess key parameters. The extent of clinical validation may vary and may involve establishing a reference range based on analysis of an apparently healthy cohort [37], verifying a reported clinical cut-off or medical decision limit (CLSI), or establishing a clinical cut-off [38]. LIMS Laboratory Information Management System, HIS Health Information System.