Why do we do a short synacthen test?
A short synacthen test is done to check the function of the adrenal gland. This can also indirectly reflect the function of the pituitary gland
What does it involve?
A short synacthen test is done as a day case. you will need to come into the hospital at 9 AM (ideally fasting). In hospital you wil be met by the nurse who will put in a canula ( a line into your vien so that you do not require repeated injections,. Following this you will have a “baseline blood test”. Following this you will be given an injection of synacthen 250 mcg. This can be given intravenously or intramuscularly. 30 minutes later you will have another blood test for cortisol.
Are there any side effects?
Synacthen stands for ” SYNthetic ACTH”  the chemical name is tetracosacteride. It is well tolerated although some people can have allergic reactions. Very very Occasionally this can be sever and include anaphylaxis (life threatening allergy). This is the reason we do this test only in hospital. 
When can I know the results?
the results are usually available in a week and your doctor will be able to get this result to you.. 
I am concerned, what should I do?
Contact Dr. George who can discuss alternatives with you.   

INDICATION

  1. Used to make a diagnosis of hypoadrenalism ( Addisons)
  2. Can be used to check the recovery of adrenals after you have been on steroids
  3. Diagnosis of congenital adrenal hyperplasia.

PREPARATION

  • If you are on hydrocortisone, take your usual dose at midday the previous day, omit the evening dose.
  • If you are on the pill or on menopausal hormone treatment, it needs to stop 6 weeks prior ( Oestrogen increases CBG).
  • For CAH do this test in the first 2 weeks after your periods (before ovulation)

You need

  • 20 guage  cannula.
  • 10 ml Saline flush.
  • syringes
  • 3 clotted tubes

If ACTH is being measured

  • 1 EDTA tube (purple top Vacutainer) Transport sample on ice.
  •  250 micrograms Synacthen.

METHOD

  1. 0900  AM   : Sample 1 for cortisol and other baseline tests ( if any)
  2. 09:00 AM  : Sample 1 for  ACTH ( on ice transport to lab ASAP)
  3. Give 250 micrograms synacthen tetracosactride i.m. OR i.v.
  4. 0930 AM : Sample 2  for cortisol.
  5. 1000 AM : Take 3 ml blood for cortisol.

INTERPRETATION

Normal if sample at 30 minutes is >450 nmol/l and or has risen above 200 nmol/l from baseline.