Evaluation of Evening Salivary Cortisone vs 48-hour Low Dose Dexamethasone Suppression Test in the Investigation of Cushing

Yasitha Illangasekera; Anish Patil; Hannah Brown; Mathilde Mordaunt; Tara Keaney; Waseem Majeed; Rupinder Kochhar; Akheel Syed; Rajshekhar Mudaliar; Fahmy Hannah; David Marshall; Ian Laing; Brian Keevil; Adrian Heald

doi:10.1530/endoabs.117.P6

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Endocrine Abstracts (2026) 117 P6 | DOI: 10.1530/endoabs.117.P6

SFEBES2026 Poster Presentations Adrenal and Cardiovascular (54 abstracts)

Evaluation of Evening Salivary Cortisone vs 48-hour Low Dose Dexamethasone Suppression Test in the Investigation of Cushing’s Syndrome

Yasitha Illangasekera ^1,2 , Anish Patil ³ , Hannah Brown ³ , Mathilde Mordaunt ⁴ , Tara Keaney ^4,3 , Waseem Majeed ^4,3 , Rupinder Kochhar ³ , Akheel Syed ^4,3 , Rajshekhar Mudaliar ^4,3 , Fahmy Hannah ⁵ , David Marshall ⁶ , Ian Laing ⁷ , Brian Keevil ⁶ & Adrian Heald ^3,4

Author affiliations

¹Sheffield Hallam University, Sheffield, United Kingdom; ²Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka; ³Salford Royal Hospital, Salford, United Kingdom; ⁴University of Manchester, Manchester, United Kingdom; ⁵University Hospital North Midlands, Stoke on-Trent, United Kingdom; ⁶Wythenshawe Hospital, Manchester, United Kingdom; ⁷Royal Preston Hospital, Preston, United Kingdom

Introduction: Cortisol secretion follows a circadian rhythm, and loss of this diurnal variation with sustained hypercortisolaemia is strongly suggestive of Cushing’s syndrome. While serum cortisol day curves are informative, they are impractical for routine clinical use. Salivary cortisone, a stable and non-invasive biomarker reflecting circulating free cortisol, may offer a convenient and patient-friendly alternative for assessing cortisol dynamics outside hospital settings. This study evaluated the diagnostic performance of salivary cortisone in patients investigated for suspected Cushing’s syndrome.

Aim: To compare the diagnostic accuracy of evening salivary cortisone with results from the Low-Dose Dexamethasone Suppression Test (LDDST) in patients with Cushing’s syndrome or mild autonomous cortisol secretion (MACS).

Methods: Patients attending a tertiary endocrine centre with confirmed or suspected Cushing’s syndrome or MACS were included. Late-night salivary cortisone samples (9 pm–midnight) were analysed using tandem mass spectrometry and compared with 48-hour serum cortisol results following LDDST. Receiver operating characteristic (ROC) analyses assessed diagnostic accuracy and identified optimal salivary cortisone thresholds for hypercortisolism.

Results: The cohort included four patients with pituitary Cushing’s, four with adrenal Cushing’s, eleven with MACS, and thirteen without biochemical evidence of hypercortisolism. For Cushing’s syndrome, the area under the ROC curve (AUC) was 0.974 ± 0.041 (95% CI 0.894–1.000; P < 0.001), indicating excellent diagnostic accuracy. The optimal late-night salivary cortisone threshold was 17.4 nmol/l (sensitivity = 0.875, specificity = 0.958, Youden’s J = 0.833). For MACS, a threshold of 7.0 nmol/l yielded an AUC = 0.983 ± 0.029 (95% CI 0.925–1.000; P < 0.001), with sensitivity = 0.933, specificity = 0.917, and Youden’s J = 0.850. Salivary cortisone correlated strongly with post-LDDST serum cortisol (r = 0.86, P < 0.001).

Conclusion: Evening salivary cortisone demonstrates excellent diagnostic accuracy and may provide a practical, reliable alternative to the LDDST for evaluating hypercortisolism.