Reference values for IGF-I serum concentration in an adult population: use of the VARIETE cohort for two new immunoassays

Autor: Nadia Sabbah, Peter Wolf, Céline Piedvache, Séverine Trabado, Tristan Verdelet, Catherine Cornu, Jean-Claude Souberbielle, Philippe Chanson
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Endocrine Connections, Vol 10, Iss 9, Pp 1027-1034 (2021)
Druh dokumentu: article
ISSN: 2049-3614
DOI: 10.1530/EC-21-0175
Popis: Objective: Measurement of IGF-I is important in the management of patients with growth hormone disorders. Here we aim to establish normative data for two new IGF-I assay kits based on a large random sample of the French general adult population. Subjects and methods: We measured IGF-I in 911 healthy adults (18–90 years) with two immunoassays (ROCHE Elecsys® and IMMULITE-2000 calibrated against the new IS 02/2547). We compared the data with those of the six immunoassays (iSYS, LIAISON XL, IMMULITE-2000 calibrated against the first IS 87/518, IGF-I RIAC T, Mediagnost ELISA, and Mediagnost RIA) that we reported previously. The pairwise concordance among the eight assays was assessed with Bland–Altman plots for both the IGF-1 raw data and the standard deviation scores (SDS), as well as with the percentage of observed agreement and the weighted Kappa coefficient for categorizing IGF-I SDS (ClinicalTrials.gov Identifier: NCT01831648). Results: The normative data included the range of values (2.5–97.5 percentiles) given by the two new IGF-I assays according to age group and sex. A formula for the SDS calculation is provided. As for the previous six assays, the lower limits of the reference intervals of the two new assays were similar, but the upper limits varied markedly. The pairwise concordances were only moderate (kappa 0.57). Conclusions: Data obtained for these two new IGF-I immunoassays confirm that despite being obtained in the same large healthy population, the reference intervals of the eight commercial IGF-1 assay kits showed noteworthy differences. The a greement among the various methods was moderate to good.
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