Endocrine Connections (Dec 2022)
Confounding effects of liquorice, hydrocortisone, and blood contamination on salivary cortisol but not cortisone
Abstract
Objective: To determine the effects of liquorice consumption, topical hydro cortisone, and blood contamination on salivary cortisol and cortisone concentrations. Design and methods: Thirty healthy volunteers were randomized to a low, medium, or high dose of liquorice. Late-night saliva samples were colle cted using a Salivette® collection device at baseline, during 1 week of daily liquorice consumption, and during 4 weeks' washout. Saliva sampling was also performed before and after the application of topical hydrocortisone on the skin. Furthermore, in a subgroup (n = 16), saliva and venous blood were collected from each individual and mixed to achieve graded blood contamination in saliva. Salivary cortisol and cortisone were a nalyzed with liquid chromatography-tandem mass spectrometry. Results: Significant increases in salivary cortisol concentrations were o bserved during medium- (+49%) and high-dose (+97%) liquorice intake, which ret urned to baseline 4 days after liquorice withdrawal. Topical hydrocortisone on finge rs holding the collection swab increased salivary cortisol concentrations >1000-fold with concomitant pronounced elevation of the cortisol:cortisone ratio. Salivary cortisol in creased significantly after contamination with blood ≥0.5%. Visual examination could safely detect these samples. Salivary cortisone concentrations were unaffected by liquorice c onsumption and blood contamination, and only marginally affected by topical hydrocort isone. Conclusion: Liquorice, topical hydrocortisone, and blood contamination may all cause elevated salivary cortisol concentrations. Improved sampling instructions and visual examination of the sample may minimize these risks. Salivary cortisone is essentially unaffected by the different preanalytical confounders and may be used as a first-line screening test for Cushing's syndrome.
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