A quantitative LC-MS/MS method for insulin-like growth factor 1 in human plasma

Area of Science:

• Biochemistry
• Analytical Chemistry
• Clinical Diagnostics

Background:

• Insulin-like Growth Factor 1 (IGF1) serves as a crucial biomarker in medical applications and doping control.
• Accurate quantification of IGF1 is essential for various diagnostic and forensic purposes.

Purpose of the Study:

• To develop and validate a robust LC-MS/MS method for precise IGF1 quantification in human plasma.
• To enable discrimination between different IGF1 proteoforms and ensure reliable measurement across a clinically relevant range.

Main Methods:

• A novel LC-MS/MS assay was established using 15N-IGF1 as an internal standard.
• The method incorporates urea-based dissociation of IGF1/IGFBP complexes followed by tryptic digestion and SPE.
• Detection of two signature peptides allows for total IGF1 quantification and proteoform discrimination.

Main Results:

• The validated method accurately measures plasma IGF1 concentrations from 10-1000 ng/mL.
• Excellent correlation (R2>0.97) was observed when compared to an established IGF1 immunoassay, with no proportional bias after normalization.
• Variability in commercial IGF1 preparations was identified, highlighting inconsistencies in purity and concentration.

Conclusions:

• The developed LC-MS/MS method provides reliable quantification of plasma IGF1 by employing urea-based complex dissociation.
• The assay effectively measures clinically relevant IGF1 levels without requiring protein-level enrichment, minimizing sample preparation losses.
• This method offers a significant advancement for accurate IGF1 analysis in clinical and doping control settings.