Multi-laboratory evaluation of immunoaffinity LC–MS-based glucagon-like peptide-1 assay: Supplementary data

Background: Although the fit-for-purpose approach has been proposed for biomarker assay validation,
practical data should be compiled to facilitate the predetermination of acceptance criteria. Methods:
Immunoaffinity LC–MS was used to analyze glucagon-like peptide-1 as a model biomarker in six
laboratories. Calibration curve, carryover, parallelism, precision, relative accuracy and processed sample
stability were evaluated, and their robustness among laboratories was assessed. The rat glucagon-like
peptide-1 concentrations in four blinded samples were also compared. Results: The obtained results and
determined concentrations in the blinded samples at all laboratories were similar, with a few exceptions,
and robust, despite the difference in optimization techniques among laboratories. Conclusion: The
results provide insights into the predefinition of the acceptance criteria of immunoaffinity LC–MS-based
biomarker assays.