The performance and reproducibility of late-night salivary cortisol estimation by enzyme immunoassay for screening Cushing disease.

Objective: Our study aimed to establish a local reference range for late-night salivary cortisol (LNSC) using enzyme immunoassay (EIA) and to study the intra-individual reproducibility of LNSC.

Methods: Prospective study involving 30 healthy subjects (HS) with body mass index (BMI) <25 kg/m2, 37 obese/overweight subjects (OS) with BMI >25 kg/m2 and 28 patients with Cushing disease (CD). Salivary sampling was performed on 2 consecutive nights and assayed by EIA.