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Pituitary Disorders/Neuroendocrinology

(4.16) Comparison of Late-Night Salivary Cortisol by ECLIA and LC-MS/MS and 24-H urinary free cortisol in diagnosis of Cushing Syndrome

Thursday, May 9, 2024
12:25 PM – 12:40 PM CDT
Location: ePoster Showcase, Empire Ballroom Foyer, Level 2

    Submitter(s)

  • LIANG-YU LIN, MD, PhD

    Attending Physician, Associate Professor
    Taipei Veterans General Hospital
    TAIPEI CITY, Taiwan (Republic of China)

Objective :

Objective: Endocrine Society recommends late-night salivary cortisol (LNSC) level as one of the first-line tests for endogenous hypercortisolism. Employing electrochemiluminescence immunoassay (ECLIA-F), the measurement of late-night salivary cortisol serves as a leading screening tool for Cushing syndrome (CS), demonstrating a sensitivity and specificity exceeding 90%. Nevertheless, a liquid chromatography-tandem mass spectrometry method has been developed to simultaneously measure cortisol (LCMS-F) and cortisone (LCMS-E). This method may offer superior performance in diagnosing CS compared to the ECLIA-F approach.

Methods:

Methods: We conducted a prospective study of the diagnostic efficacy of ECLIA-F, LCMS-F, and LCMS-E in late-night saliva samples obtained from patients with CS and subjects with non-functioning adrenal incidentaloma as control group from September 2021 to November 2023 at Taipei Veteran General Hospital in Taiwan. At least one twenty-four hours urinary cortisol (UFC) obtained simultaneously with late-night saliva by all enrolled subjects.

Results:

Results: A total of thirty-four subjects with nineteen female were enrolled. Twenty-five patients (41.4±15.9 year-old) had an established diagnosis of CS by pathology were included, 15 with Cushing's disease. All patients with CS for which ECLIA-F had a high sensitivity (92.0%) of diagnosis and significant elevations of LNSC (1526.0±1253.0 v.s. 68.6±18.2 ng/dL, p=0.019) compared with control. In contrast, LCMS-F and LCMS-E had lower sensitivity (64.0% and 80%). ECLIA-F had poor sensitivity (71.4%) for adrenocorticotropic hormone (ACTH)-independent CS (5 patients with at least 1 and 2 without any elevated salivary result). Half patients with non-functioning adrenal incidentaloma had elevation of LCMS-F. The sensitivity of UFC is 92% similar to the late-night salivary cortisol by ECLIA-F in patients with CS who had significant elevation of UFC than control group (958.0±1081.3 v.s. 68.9±24.2 ug/day, p=0.032).

Discussion/Conclusion:



Conclusion: Late-night salivary cortisol by ECLIA appears similar sensitive to UFC in the diagnosis of CS. Since the half of patients with non-functioning adrenal incidentaloma have elevated late-night salivary cortisol by LCMS-F, a single elevated level of LCMS-F has poor specificity. LNSC measured by ECLIA is a sensitive test for ACTH-dependent Cushing syndrome but not for ACTH-independent CS. We suggest that whether LCMS-F nor LCMS-E improves the sensitivity of late-night ECLIA-F for CS still need to investigate in large cohort study.