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Hydrocortisone Day Curve (HCDC)

INDICATION

To establish the correct dose and distribution of hydrocortisone replacement therapy throughout the day.

CONTRAINDICATIONS

None

SIDE EFFECTS

None

PREPARATION

Stop all oestrogen therapy 6 weeks prior to test.
No need to fast.
Take normal morning hydrocortisone and patient should note down actual time taken.
19g cannula.
Red top Vacutainers.
Syringes.

METHOD

Take blood at the following times:

  • Blood sample on arrival, noting time of sample and time and dose of hydrocortisone.
  • Pre lunchtime (2nd) dose
  • 1 hour post lunchtime (2nd) dose
  • pre evening (3rd) dose
  • post evening (3rd) dose or at 6pm.

INTERPRETATION

Aim for adequate cortisol levels throughout the day (peak <900 nmol/l, trough >100 nmol/l).