Abstract | BACKGROUND AND AIM: MATERIALS AND METHODS: We studied 200 subjects: 125 patients were considered retrospectively and 75 were enrolled prospectively as the validation cohort. Serum dexamethasone, Late Night Salivary Cortisol (LNSC), and Urinary Free Cortisol (UFC) were measured with LC-MS/MS. Normal LNSC and UFC levels were used to exclude CS. The lower 2.5th percentile of dexamethasone distribution in non-CS patients with cortisol ≤ 50 nmol/L after 1-mg DST was used as threshold. RESULTS: 16 patients were CS and 184 non-CS (108 adrenal incidentaloma and 76 excluded CS); 4.5 nmol/L resulted the calculated threshold. Cortisol after 1-mg DST confirmed high sensitivity (100% at 50 nmol/L cut-off) and moderate-low specificity (63%, increased to 91% at 138 nmol/L) to diagnose CS in the whole cohort of patients. We could reduce the number of false-positive results (from 10 to 6 and from 7 to 4 in AI and excluded CS) considering adequate dexamethasone levels. Dexamethasone levels were not affected by hypercortisolism, age, gender, smoke, weight, and creatinine. 6% of non-CS patients did not achieve adequate dexamethasone levels (40% of tests with serum cortisol > 138 nmol/L after 1-mg DST). CONCLUSIONS: We developed and validated the routine dexamethasone measurement during 1-mg DST: it is independent from patient's clinical presentation, and it should be used to increase the specificity of serum cortisol levels.
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Authors | F Ceccato, C Artusi, M Barbot, L Lizzul, S Pinelli, G Costantini, S Niero, G Antonelli, M Plebani, C Scaroni |
Journal | Journal of endocrinological investigation
(J Endocrinol Invest)
Vol. 43
Issue 8
Pg. 1105-1113
(Aug 2020)
ISSN: 1720-8386 [Electronic] Italy |
PMID | 32060745
(Publication Type: Journal Article, Validation Study)
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Chemical References |
- Biomarkers
- Glucocorticoids
- Dexamethasone
- Hydrocortisone
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Topics |
- Adult
- Aged
- Biomarkers
(blood)
- Case-Control Studies
- Cushing Syndrome
(blood, diagnosis, drug therapy, epidemiology)
- Dexamethasone
(administration & dosage, blood)
- Dose-Response Relationship, Drug
- Female
- Follow-Up Studies
- Glucocorticoids
(administration & dosage, blood)
- Humans
- Hydrocortisone
(blood)
- Italy
(epidemiology)
- Male
- Middle Aged
- Prognosis
- Prospective Studies
- Retrospective Studies
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