A quantitative LC-MS/MS method for insulin-like growth factor 1 in human plasmaBronsema, K. J., Klont, F., Schalk, F. B., Bischoff, R., Kema, I. P. & van de Merbel, N. C., Nov-2018, In : Clinical chemistry and laboratory medicine. 56, 11, p. 1905-1912 8 p.
Research output: Contribution to journal › Article › Academic › peer-review
Background: Insulin-like growth factor 1 (IGF1) is a biomarker with various applications in medicine and also in doping control.
Methods: A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed that employs 15N-IGF1 as an internal standard. The method features urea-based IGF1/IGFBP-complex dissociation which is directly followed by tryptic digestion. Following solidphase extraction (SPE) sample clean-up of the digest, IGF1 is detected by means of two signature peptides that enable quantification of total IGF1 as well as discrimination between IGF1 proteoforms with 'native' and modified or extended N-terminal sequences.
Results: Our method is capable of measuring plasma IGF1 concentrations over the clinically relevant range of 10-1000 ng/mL and was validated according to regulatory guidelines. Comparison with the IDS-iSYS IGF1 immunoassay revealed good correlation (R-2 > 0.97) and no proportional bias between both assays was observed after normalizing the results against the WHO reference standard for IGF1 (02/254). Evaluation of several commercially available IGF1 preparations showed varying responses which were due to inconsistencies in purity and absolute amount of IGF1 present in these products.
Conclusions: Our LC-MS/MS method introduces urea-based dissociation of IGF1/IGFBP-complexes to enable reliable quantification of IGF1 in plasma. Furthermore, the method is able to detect clinically relevant IGF1 levels without an enrichment procedure at the protein-level and thereby minimizes the risk of losing IGF1 proteoforms during sample preparation.
|Number of pages||8|
|Journal||Clinical chemistry and laboratory medicine|
|Early online date||2018|
|Publication status||Published - Nov-2018|
- insulin-like growth factor 1 (IGF1), liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), quantification, CHROMATOGRAPHY/TANDEM MASS-SPECTROMETRY, FACTOR-I, GH DEFICIENCY, IGF-I, BIOLOGICAL SAMPLES, HORMONE ABUSE, QUANTIFICATION, PROTEINS, SERUM, PERFORMANCE