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Published on: August 23, 2019
National comparability and inter-laboratory performance of cortisol immunoassays and LC-MS/MS methods
Jacquelien J Hillebrand1,2, Judith A P Bons3, Sjoerd A A van den Berg4,5
1Department of Laboratory Medicine, Endocrine Laboratory, Amsterdam UMC Location University of Amsterdam, Amsterdam, The Netherlands.
Clinical Chemistry and Laboratory Medicine
|June 22, 2026
Summary
Cortisol assay variability impacts endocrine testing. Roche and Abbott immunoassays show acceptable comparability and performance, suggesting no need for national standardization.
Area of Science:
- Clinical Chemistry
- Endocrinology
- Laboratory Medicine
Background:
- Cortisol measurements are crucial for diagnosing endocrine disorders.
- Variations in cortisol assays can affect the interpretation of dynamic testing results.
- Standardization is needed to ensure comparability of cortisol measurements across different laboratories and assays.
Purpose of the Study:
- To evaluate the comparability of various cortisol immunoassays against liquid chromatography-tandem mass spectrometry (LC-MS/MS).
- To assess the inter-laboratory performance of these cortisol immunoassays.
- To determine if national standardization of serum cortisol measurements is necessary.
Main Methods:
- Serum samples from 45 participants were analyzed.
- Immunoassays from Roche, Abbott, Siemens, and Beckman Coulter were compared with LC-MS/MS.
- Passing-Bablok regression, Bland-Altman analysis, and inter-laboratory imprecision were assessed.
Main Results:
- Roche and Abbott immunoassays demonstrated good agreement and acceptable inter-laboratory performance compared to LC-MS/MS.
- The original Siemens immunoassay showed poor agreement, but the improved Siemens CSI assay had a bias of 4.9%.
- Beckman Coulter assay exhibited high imprecision, and the original Siemens assay had significant bias.
Conclusions:
- Roche and Abbott cortisol immunoassays are comparable and perform acceptably between laboratories.
- Improvements in the Siemens assay significantly reduced bias, highlighting the potential for assay enhancement.
- Current findings suggest no immediate need for a national standardization program for serum cortisol measurements.
