Cortisol standards

Saliva was collected via the Sarstedt Salivette Synthetic Swab saliva collection system (Catalogue # 51.1534.500 Sarstedt, Newton, NC 28658, USA). Samples were stored at −30 °C until assayed for cortisol by radioimmunoassay. Primary antibodies raised against cortisol-3-O-carboxymethyloxime-BSA and iodine labeled cortisol were purchased from MP Biomedicals. Cortisol standards were purchased from Sigma Chemical, anti-rabbit globulin serum in conjunction with polyethylene glycol was used for separation of the bound and free fractions. All samples and standards were analyzed in duplicate. The intra and inter-assay coefficient of variation was 4.7% at 1 ng/ml and 7.4% at 0.25 ng/ml, respectively.

Saliva was collected via the Sarstedt Salivette Synthetic Swab saliva collection system (Catalogue # 51.1534.500 Sarstedt, Newton, NC 28658, USA). Participants were required to leave the cotton swab in their mouth for 3–5 min to obtain an adequate sample. Swabs were then sealed in the plastic cover tube of the salivette, and placed in a −20° freezer within two hours. Samples were shipped on dry ice to the New York State Psychiatric Institute’s central reference laboratory in Orangeburg, NY where they were assayed.
Salivary cortisol was measured by radioimmunoassay. Primary antibodies raised against cortisol-3-O-carboxymethyloxime-BSA and iodine labeled cortisol were purchased from MP Biomedicals. Cortisol standards were purchased from Sigma Chemical, Anti rabbit globulin serum in conjunction with polyethylene glycol was used for separation of the bound and free fractions. All samples and standards were analyzed in duplicate. The intra and inter-assay coefficient of variation was 4.7% at 1 ng/mL and 7.4% at 0.25 ng/mL, respectively.