Bias in IGF-1 concentrations and interpretation across three different clinical laboratory assays

Zahraa Mohammed-Ali, Sarah Delaney, Ravinder Singh, Felix Leung, Jennifer Taher, Jeannette Goguen, Julie Gilmour, Lusia Sepiashvili, Daniel R. Beriault

Research output: Contribution to journalArticlepeer-review

Abstract

In this study, we compared the DiaSorin LiaisonXL IGF-1 immunoassay to both the Roche Elecsys IGF-1 immunoassay and to the liquid chromatography-high resolution mass spectrometry (LC–MS) IGF-1 assay. Our study shows a constant positive bias in DiaSorin compared to the Roche immunoassay (mean 42 μg/L, 24%), and a proportional positive bias in DiaSorin compared to the LC–MS method (mean 49 μg/L, 29%). Further, we demonstrate the potential clinical impact of this bias by evaluating 43 adult samples, collected over a 2-month period, which were shown to be discrepant based on a chart review. Despite the positive analytical bias in the Diasorin assay compared to the LC–MS assay, the Diasorin assay upper reference limits were lower than those of the LC–MS assay. This effect caused nine out of forty-three samples to show falsely elevated results when they were clinically diagnosed as negative for acromegaly. Discussed in the context of previous literature, our findings emphasize the importance of adjusting reference intervals for IGF-1 assays based on the clinical needs of a patient population.

Original languageEnglish (US)
Pages (from-to)14-19
Number of pages6
JournalClinical Biochemistry
Volume108
DOIs
StatePublished - Oct 2022

Keywords

  • Acromelagy
  • Diasorin Liaison XL
  • Giagantism
  • IGF-1 immunoassay
  • LC–MS
  • Method comparison
  • Roche Elecsys

ASJC Scopus subject areas

  • Clinical Biochemistry

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