Reference Range
Urinary free cortisol measurements are used primarily in the diagnosis of hypercortisolism caused by Cushing syndrome.
Reference ranges for urinary free cortisol vary by age, as follows:
Age 0-2 years – Not established
Age 3-8 years – 1.4-20 µg/24 h
Age 9-12 years – 2.6-37 µg/24 h
Age 13-17 years – 4-56 µg/24 h
Age 18 years or older – 3.5-45 µg/24 h
Conversion factor
Cortisol: µg/24 h X 2.76 = nmol/24 h (molecular weight = 362.5)