SAT299 Comparison Of Plasma Cortisol-, Salivary Cortisol- And Salivary Cortisone-response To The Short Synacthen Test In Women Using Oral Contraceptives

Disclosure: N. Bäcklund: None. S. Lundstedt: None. T. Olsson: None. P.M. Dahlqvist: None. G. Brattsand: None. Introduction: The short Synacthen test (SST) is a cornerstone in the diagnosis of adrenal insufficiency (AI). However, cortisol levels in serum or plasma may be misleadingly elevated by estrogen containing oral contraceptives (OCs), due to increased levels of cortisol binding protein (CBG). This may falsely declare a woman with AI to be cortisol sufficient. Salivary cortisol and cortisone closely correlate with the unbound fraction of plasma cortisol and is thus less likely to be influenced by variations in CBG levels. Our hypothesis was that the salivary cortisol and cortisone response to SST would be similar in women with and without OC use. Materials and methods: A standard intravenous 250 µg SST was performed in 87 women without known diseases or medications affecting the cortisol axis, 41 using OCs containing ethinylestradiol and 46 controls. Plasma cortisol was analyzed by Roche Elecsys Cortisol II assay and salivary cortisol and cortisone by LC-MS/MS in samples collected at baseline (time 0), and 30 and 60 minutes after Synacthen injection. The effect of OCs upon plasma cortisol, salivary cortisol and salivary cortisone was assessed by a two-way ANOVA with sampling time after SST as repeated measure. Results: There was an overall effect of OCs on plasma cortisol, but not on salivary cortisol or cortisone. Plasma cortisol levels were considerably higher in the OC group vs. controls at all time points; +150% at 0 minutes; +90% at 30 minutes; and +86% at 60 minutes. There was a significant interaction between OC use and sample time point for both salivary cortisol and cortisone. Mean salivary cortisol in women using OCs was 37% higher vs. controls at 0 minutes but was instead lower in the OCs group at 30 and 60 minutes after SST (-13% and -11%, respectively). Similarly, mean salivary cortisone was also slightly higher in the OC group than controls at baseline (+13%) and somewhat lower at 30 and 60 minutes (-6% and -7%). Conclusion: Plasma cortisol levels during an SST were significantly elevated in women using OCs containing estrogen whereas OC effects upon salivary cortisol and cortisone levels were modest, especially for salivary cortisone. Analysis of salivary cortisone is a promising alternative to plasma cortisol for diagnosis of AI in women using OCs. Presentation: Saturday, June 17, 2023