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Effect of albumin concentration on serum cortisol measured by the Bayer Advia Centaur assay

S C Barnes1, R Swaminathan

  • 1St Thomas' Hospital, Lambeth Palace Road, London SE1 7EH, UK. sophie.barnes@gstt.nhs.uk

Annals of Clinical Biochemistry
|February 3, 2007
PubMed

Insights

Albumin levels significantly impact cortisol test accuracy. The Bayer Advia Centaur assay shows under-recovery with low albumin, affecting adrenal insufficiency diagnosis in critically ill patients.

Area of Science:

  • Clinical Chemistry
  • Endocrinology
  • Laboratory Medicine

Background:

  • Discrepancies noted between Bayer Advia Centaur and Roche Elecsys cortisol assays.
  • Assays were performed on samples from endocrine outpatients and intensive therapy unit patients.

Purpose of the Study:

  • To investigate the influence of albumin concentration on the performance of two cortisol assays.
  • To identify factors contributing to observed differences between the Bayer Advia Centaur and Roche Elecsys cortisol methods.

Main Methods:

  • Retrospective analysis of patient samples with recorded albumin concentrations.
  • Performed recovery experiments using samples with varying albumin and cortisol levels.

Main Results:

  • Albumin concentration explained nearly 50% of the variability in results between the two cortisol assays.
  • The Bayer Advia Centaur assay demonstrated significant under-recovery when albumin concentrations fell below 24 g/L.

Conclusions:

  • Low albumin concentrations critically affect the accuracy of the Bayer Advia Centaur cortisol assay.
  • This under-recovery poses a diagnostic challenge for adrenal insufficiency in critically ill patients with hypoalbuminemia.
Abstract

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