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Updated: Jul 14, 2026
Homogeneous Time-resolved Förster Resonance Energy Transfer-based Assay for Detection of Insulin Secretion
Published on: May 10, 2018
Pilot study for the standardization of insulin immunoassays with isotope dilution liquid chromatography/tandem mass
Diego Rodríguez-Cabaleiro1, Katleen Van Uytfanghe, Veronique Stove
1Laboratory for Analytical Chemistry, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium.
Background:
An international working group convened by the American Diabetes Association (ADA) called for a reference measurement procedure for use in a trueness-based standardization project of insulin immunoassays. In view of this demand, we conducted a pilot study to investigate the feasibility of such a standardization project with our isotope dilution-liquid chromatography/tandem mass spectrometry (ID-LC/tandem MS) procedure.
Methods:
We evaluated the precision, accuracy, and limit of quantification (LoQ) of the ID-LC/tandem MS procedure by use of insulin-free serum supplemented with insulin to give 3 pools with concentrations of 0.0796, 0.769, and 5.56 microg/L. We conducted a pilot method comparison study with 4 immunoassays and 80 samples from fasting and glucose-stimulated patients.
Results:
The within-run and total imprecision (CV) ranged from 3.2% to 6.3% and from 4.9% to 12.1% (listing sequence from the high to the low pool). The recovery from supplemented insulin-free sera ranged from 101.8% to 104.1%, and the LoQ was 0.07 microg/L (12 pmol/L). Weighted Deming regression and correlation analysis of the method-comparison data showed considerable between-assay variation for the immunoassays but, with the exception of one assay, excellent correlation with ID-LC/tandem MS. Recalibration of the immunoassay results considerably reduced the between-assay variation. Moreover, after recalibration, 3 of the 4 assays fulfilled the total error specification of 32% proposed by the ADA Workgroup.
Conclusions:
Recalibration of insulin assays by regression equations established from method comparison with ID-LC/tandem MS can result in successful standardization and fulfillment of the total error criterion proposed by the ADA Workgroup.
