Top-down quantification of insulin-like growth factor-I in human serum by liquid chromatography coupled with high-resolution mass spectrometry

Currently, quantification of IGF-I is relevant to doping control as a biomarker of growth hormone (GH) abuse, but also to the clinical field for longitudinal follow-up of patients with disorders related to the GH axis. In the past years, top-down liquid-chromatography coupled with high-resolution mass spectrometry (LC-HRMS) has gained popularity. Mainly because it is more straightforward than the bottom-up approach, which requires a trypsin digestion step. Hereby, a simple, validated top-down LC-HRMS method for rapid quantification of IGF-I in human serum is presented. The assay requires minimal sample preparation in combination with a short instrumental analysis and its performance is additionally compared with the IDS-iSYS immunoassay.