Ri. Gafni et al., Nighttime salivary cortisol measurement as a simple, noninvasive, outpatient screening test for Cushing's syndrome in children and adolescents, J PEDIAT, 137(1), 2000, pp. 30-35
Objective: There is currently no optimal test to screen for endogenous Gush
ing's syndrome (GS in children. Traditional 24-hour urine or midnight serum
cortisol values may be difficult to obtain or elevated by venipuncture str
ess. We hypothesized that salivary cortisol measurement is a reliable way t
o screen for CS in children.
Study design: Sixty-seven children (5-17 years) were studied: 24 obese volu
nteers, 29 non-obese volunteers, and 14 children with CS. Saliva was obtain
ed at 7:30 AM, bedtime, and midnight for measurement of free cortisol by ra
dioimmunoassay.
Results: Salivary cortisol was detectable in all morning and evening sample
s from patients with CS but was frequently undetectable in healthy children
at bedtime (66% and at midnight (90%). With cut points that excluded healt
hy children, a midnight salivary cortisol value of 7.5 nmol/L (0.27 mu g/dL
) identified 13 of 14 patients with CS, whereas a bedtime value >27.6 nmol/
L (1 mu g/dL) detected CS in 5 of 6 patients. The diagnostic accuracies of
midnight salivary cortisol and urinary free cortisol per square meter were
the same (93%).
Conclusion: Salivary cortisol measurement at bedtime or midnight rules out
CS in nearly all cases. Nighttime salivary cortisol sampling is thus a simp
le, accurate way to screen for hypercortisolism in children.