Introduction
As proteomic initiatives make headway in biomarker discovery andgeneral protein cataloguing, it becomes imperative to be able to repeatedly screen for the same target proteins from thousands ofindividuals for clinical investigation and biomarker validation. Clincal proteomics technologies have matured over the pastdecade, conventional approaches are still not capable of routine lyperforming such analyses and have therefore been subjugated by classical immunoassay platforms for such population screening. However, these methodologies are inherently blind to the structural diversity found within any human population that are caused by genetic and/or post translational modifications, which may ultimately influence biomarker behavior. Such problems can be resolved through novel affinity-based mass spectrometry approaches. Shown here is the development and validation of such a mass spectrometric immunoassay (MSIA), targeting the human biomarker insulin like growth factor 1.