Determination of Very Low Abundance Diagnostic Proteins in Serum Using Immunocapture LC-MS/MS.

The use of antibodies in "bottom-up" liquid chromatography-mass spectrometry (LC-MS) workflows to determine low-abundance biological active proteins in complex human samples has increased in recent years: immunocapture analysis combines the workflow of conventional immunological assays with LC-MS analysis. This article describes typical challenges, such as cross reactivity and the mass spectrometer's dynamic range, as well as the advantages of isoform differentiation and multiplexing. Additionally, some experimental formats of immunocapture bottom-up LC-MS analysis of biological active proteins in complex human samples are discussed. [ABSTRACT FROM AUTHOR]