Bedtime Salivary Cortisol as a Screening Test for Cushing Syndrome in Children
Peer reviewed, Journal article
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Original versionJournal of the Endocrine Society (JES). 2021, 5 (5), 1-8. 10.1210/jendso/bvab033
Abstract Background:Diagnosing Cushing syndrome (CS) can be challenging. The 24-hour urine free cortisol (UFC) measurement is considered gold standard. This is a laborious test, de-pendent on correct urine collection. Late-night salivary cortisol is easier and is used as a screening test for CS in adults, but has not been validated for use in children. Objective:To define liquid chromatography tandem mass spectrometry (LC-MS/MS)-based cutoff values for bedtime and morning salivary cortisol and cortisone in children, and validate the results in children with and without CS. Methods:Bedtime and morning salivary samples were collected from 320 healthy chil-dren aged 4 to 16 years. Fifty-four patients from the children’s outpatient obesity clinic and 3 children with pituitary CS were used for validation. Steroid hormones were as-sayed by LC-MS/MS. Cutoff levels for bedtime salivary cortisol and cortisone were de-fined by the 97.5% percentile in healthy subjects. Results:Bedtime cutoff levels for cortisol and cortisone were 2.4 and 12.0 nmol/L, re-spectively. Applying these cutoff levels on the verification cohort, 1 child from the obesity clinic had bedtime salivary cortisol exceeding the defined cutoff level, but normal sal-ivary cortisone. All 3 children with pituitary CS had salivary cortisol and cortisone far above the defined bedtime cutoff levels. Healthy subjects showed a significant decrease in salivary cortisol from early morning to bedtime.