SUN-477 Cross-Sectional Comparison Study of Saliva Cortisone and Saliva Cortisol Versus Current Standard-Of-Care Venipuncture-Based Cortisol Measurements

Abstract Disclosure: C.A. Villavicencio Torres: None. S. Ahmadian: None. V.M. Fell: None. K. Moehnke: None. Y. Chai: None. R.L. Taylor: None. S.K. Grebe: None. A.D. Maus: None. I. Bancos: None. Background: Current standard-of-care assessment of adrenal disorders relies on the venipuncture-based total cortisol measurements. Salivary cortisol (SalF) and cortisone (SalE) measurements have advantages such as a more accurate assessment of patients with cortisol-binging globulin abnormalities and the convenience of at-home non-invasive testing. Aims: This study aimed to compare concentrations of cortisol and dexamethasone between clinical (venipuncture-based) and saliva samples. Methodology: We conducted a cross-sectional study (July 2024-January 2025) of adults undergoing overnight dexamethasone suppression test (DST) or cosyntropin stimulation test (CST). Saliva samples were collected alongside clinical samples. Saliva measurements included cortisol, cortisone, and dexamethasone (mass spectrometry), while clinical samples were tested for total cortisol (Roche immunoassay) and, in a subgroup, dexamethasone (mass spectrometry). Results: Of 241 patients (186 (77%) women, median age 53 years (IQR 39-66)), 178 (74%) provided samples as a part of DST and 63 (26%) as a part CST. An inability to provide sufficient saliva for analysis was found in 5 patients (2%). In patients undergoing DST, median post-dexamethasone serum total cortisol was 1.3 mcg/dL (IQR 0.8-2.2), and median serum dexamethasone (SerD) was 0.43 mcg/dL (IQR 0.3-0.6) based on clinical samples, while median SalF was 10.2 ng/dL (IQR 6.6-23.6), SalE was 78.6 ng/dL (IQR 52.8-131.1), and saliva dexamethasone (SalD) was 60 ng/dL (IQR 41-93). SalE (r=0.92, p<.0001) demonstrated a stronger correlation than SalF (r=0.85, p<.0001) when compared with post-dexamethasone serum total cortisol measurements. SalD (r=0.85, p<.0001) correlated with SerD measurements. In patients undergoing CST, median baseline serum total cortisol was 7.2 mcg/dL (IQR 4.6-10) based on clinical samples, while median baseline SalF was 86.6 ng/dL (IQR 38.3-166.3), and median SalE was 707 ng/dL (IQR 347-906). Median peak 60-minute serum total cortisol was 21.5 mcg/dL (IQR 18-24), while SalF was 870.4 ng/dL (IQR 440-2904) and SalE was 2501 ng/dL (IQR 1770-3193). Both baseline (r=0.92, p<.0001) and 60 min peak post-cosyntropin SalE (r=0.84, p<.0001) demonstrated a strong correlation with venipuncture-based measurements. SalF had a weaker than SalE correlation at both baseline (r=0.88, p<.0001) and 60 min peak post-cosyntropin (r=0.79, p<.0001). Conclusion: Our study demonstrates that salivary measurements of cortisone, cortisol and dexamethasone strongly correlate with standard-of-care venipuncture concentrations following DST and CST. SalE showed the stronger than SalF correlation with venipuncture-based serum total cortisol concentrations. Presentation: Sunday, July 13, 2025