Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Observational Study
. 2022 Feb 17;107(3):e1221-e1230.
doi: 10.1210/clinem/dgab724.

Interpretation of Abnormal Dexamethasone Suppression Test is Enhanced With Use of Synchronous Free Cortisol Assessment

Natalia Genere  1   2 , Ravinder Jeet Kaur  2 , Shobana Athimulam  2   3 , Melinda A Thomas  2 , Todd Nippoldt  2 , Molly Van Norman  4 , Ravinder Singh  4 , Stefan Grebe  4 , Irina Bancos  2   4
Affiliations
Observational Study

Interpretation of Abnormal Dexamethasone Suppression Test is Enhanced With Use of Synchronous Free Cortisol Assessment

Natalia Genere et al. J Clin Endocrinol Metab. .

Abstract

Context: Interpretation of dexamethasone suppression test (DST) may be influenced by dexamethasone absorption and metabolism and by the altered cortisol binding.

Objective: We aimed to determine the normal ranges of free cortisol during DST in participants without adrenal disorders and to identify the population of patients where post-DST free cortisol measurements add value to the diagnostic workup.

Design and setting: Cross-sectional study conducted in a tertiary medical center.

Participants: Adult volunteers without adrenal disorders (n = 168; 47 women on oral contraceptive therapy [OCP], 66 women not on OCP, 55 men) and patients undergoing evaluation for hypercortisolism (n = 196; 16 women on OCP).

Measurements: Post-DST dexamethasone and free cortisol (mass spectrometry) and total cortisol (immunoassay).

Main outcome measures: Reference range for post-DST free cortisol, diagnostic accuracy of post-DST total cortisol.

Results: Adequate dexamethasone concentrations (≥0.1 mcg/dL) were seen in 97.6% volunteers and 96.3% patients. Only 25.5% of women volunteers on OCP had abnormal post-DST total cortisol (>1.8 mcg/dL). In volunteers, the upper post-DST free cortisol range was 48 ng/dL in men and women not on OCP, and 79 ng/dL in women on OCP. When compared with post-DST free cortisol, diagnostic accuracy of post-DST total cortisol was 87.3% (95% CI, 81.7-91.7); all false-positive results occurred in patients with post-DST cortisol between 1.8 and 5 mcg/dL. OCP use was the only factor associated with false-positive results (21.1% vs 4.9%, P = 0.02).

Conclusions: Post-DST free cortisol measurements are valuable in patients with optimal dexamethasone concentrations and post-DST total cortisol between 1.8 and 5 mcg/dL.

Keywords: accuracy; adrenal adenoma; adrenal mass; diagnosis; mild autonomous cortisol secretion.

PubMed Disclaimer

Figures

Figure 1.
Figure 1.
Post-dexamethasone suppression test: free cortisol vs total cortisol concentrations in (A) volunteers and (B) in patients undergoing evaluation for hypercortisolism.
Figure 2.
Figure 2.
Diagnostic accuracy of post-DST free cortisol concentrations. True-positive result was defined as a case with increased post-DST free cortisol and total cortisol. True-negative result was defined as absence of normal post-DST free cortisol and total cortisol. False-positive result was defined as abnormal post-DST total cortisol, but normal post-DST free cortisol. False-negative result was defined as normal post-DST total cortisol, but abnormal post-DST free cortisol. Abbreviations: DST: dexamethasone suppression test; OCP: oral contraceptive pill.
Figure 3.
Figure 3.
Suggested algorithm for the 1 mg overnight dexamethasone suppression test.
See this image and copyright information in PMC

References

    1. Vaidya A, Hamrahian A, Bancos I, Fleseriu M, Ghayee HK. The evaluation of incidentally discovered adrenal masses. Endocr Pract. 2019;25(2):178-192. - PubMed
    1. Fassnacht M, Arlt W, Bancos I, et al. Management of adrenal incidentalomas: European Society of Endocrinology clinical practice guideline in collaboration with the European Network for the Study of Adrenal Tumors. Eur J Endocrinol. 2016;175(2):G1-G34. - PubMed
    1. Nieman LK, Biller BM, Findling JW, et al. The diagnosis of Cushing’s syndrome: an Endocrine Society Clinical practice guideline. J Clin Endocrinol Metab. 2008;93(5):1526-1540. - PMC - PubMed
    1. Elhassan YS, Alahdab F, Prete A, et al. Natural history of adrenal incidentalomas with and without mild autonomous cortisol excess: a systematic review and meta-analysis. Ann Intern Med. 2019;171(2):107-116. - PubMed
    1. Li D, Kaur RJ, Zhang CD, et al. Risk of bone fractures after the diagnosis of adrenal adenomas: a population-based cohort study. Eur J Endocrinol. 2021;184(4):597-606. - PMC - PubMed

Publication types