Cortisol Day Curve (Cushing's Syndrome Only)

INDICATION

Assessment of control of Cushing's disease on therapy or after discontinuation of treatment.

CONTRAINDICATIONS

None

SIDE EFFECTS

None

PREPARATION

Stop all oestrogen therapy 6 weeks prior to test.
Non-fasting: breakfast and normal dose of tablets are taken at the usual time.
19g cannula.
6 red top Vacutainers.
Syringes.

METHOD

0900h }
1200h } Take blood
1500h } for cortisol
1800h } measurement
(2400h) }

INTERPRETATION

Normal response is a mean serum cortisol between 150 and 300 nmol/l, and should be maintained while patients are awaiting an adrenalectomy.
Higher levels indicate a need for increased therapy.

Random concentrations of cortisol can also be used on a day to day basis to determine effectiveness of cortisol suppression on medical treatment (with Ketoconazole (up to 400 mg bd), Metyrapone (up to 750 mg tds) or etomidate (3mg per hour by IV infusion).

REFERENCE

Trainer et al., Clin. Endo. 39, 441-443 (1993).