Cortisol assays across the physiologic spectrum: access immunoassay compared with LC-MS/MS.
Journal
European journal of endocrinology
Journal Volume
194
Journal Issue
3
Start Page
K9
End Page
K13
ISSN
1479-683X
Date Issued
2026-03-04
Author(s)
Newman, Andrew J
Mahrokhian, Sanan
Hanna, Isabelle
Salle, Stéfanie Parisien-La
Brown, Jenifer M
Stouffer, David G
Auchus, Richard J
Vaidya, Anand
Abstract
Background Immunoassays for cortisol are commonly used to evaluate adrenal function, but their similarity to gold-standard liquid chromatography-tandem mass spectrometry (LC-MS/MS) has not been demonstrated across the physiologic spectrum of cortisol production. Methods In this cross-sectional study, 97 adults without known adrenal disease underwent measurements of serum cortisol in the morning, post-dexamethasone suppression, and post-cosyntropin stimulation. Samples were analyzed on the Access Cortisol immunoassay and by LC-MS/MS. Results The assays showed good correlation across the physiologic spectrum, with close agreement at the lower end (mean bias -0.06 µg/dL [-1.7 nmol/L] post-dexamethasone suppression) and somewhat poorer agreement at the upper end of the physiologic spectrum (mean bias -1.68 µg/dL [-46.4 nmol/L] post-cosyntropin stimulation). Concordance using common interpretative cutoffs was good, with Cohen's κ = 0.93 for cortisol >10 µg/dL (275.9 nmol/L; morning), κ = 0.98 for cortisol <1.8 µg/dL (50 nmol/L; post-dexamethasone), and κ=0.89 for cortisol >14.5 µg/dL (400 nmol/L; post-cosyntropin). Conclusions Clinicians should be reassured that this immunoassay provides cortisol measurements similar to gold-standard LC-MS/MS across the physiologic continuum.
Subjects
Cushing syndrome
adrenal insufficiency
cortisol
immunoassay
mass spectrometry
Type
journal article