•Saliva sampling is easy, non-invasive, and thus suitable for outpatient settings.•HPLC-MS/MS is the gold standard, measuring cortisol and cortisone simultaneously.•Immunoassays for cortisol may cross-react with cortisone, which is abundant in saliva.•Cut-off values are lacking for salivary cortisol in adrenal dynamic tests.•Automated immunoassays for salivary cortisol can be used in first line.