Characterization of the serum and salivary cortisol response to the intravenous 250 µg ACTH1-24 stimulation test

The ACTH1–24 stimulation test is commonly used to assess the hypothalamic-pituitary-adrenal (HPA) axis. Given variations in CBG concentration and binding affinity, serum total cortisol may misclassify some patients. Salivary cortisol correlates well with serum free cortisol but is easier to measure and widely available in commercial laboratories. The aim of this study was to investigate the utility of measuring salivary cortisol during the ACTH1–24 stimulation test. Case–control study in a clinical research facility. Eighty-seven patients with suspected cortisol deficiency, twenty-four healthy controls, and ten healthy women on the oral contraceptive (OC) underwent an intravenous 250 µg ACTH1–24 stimulation test. Concordance of ACTH1–24 stimulated serum and salivary cortisol was evaluated. There was a significant difference in serum cortisol between the healthy volunteers and the women on the OC (P