Measurement of late-night salivary cortisol and cortisone by LC-MS/MS to assess preanalytical sample contamination with topical hydrocortisone

摘要

Measurement of increased late-night salivary cortisol (LNSC)1 is now a mainstay in the diagnosis of endogenous Cushing syndrome (1). Patients typically sample their saliva at home and are carefully instructed to avoid using potential contaminants, such as topical creams or ointments containing hydrocortisone (authentic cortisol). Using these creams or ointments can cause preanalytical contamination of the saliva sample that cannot be distinguished from endogenous cortisol as measured by either immunoassay or liquid chromatography-tandem mass spectrometry (LC-MS/MS).