|Congenital Adrenal hyperplasia
|Primary hyperaldosteronism (Conn's syndrome)
|McCune Albright syndrome
If 8-10am cortisol >350nmol/L, SST usually not required for assessment. If done a cortisol of >420nmol/L at 30 minutes post-Synacthen indicates an adequate adrenal response.
- It is used to test for Addison's disease or suspected ACTH deficiency
- Synthetic ACTH (ACTH 1-24) 250 mcg Tetracosactrin is given IM
- Cortisol measured at 0 and 30 minutes
- Blood taken and placed into a Serum Gold top container
- Stored in the fridge if delayed to lab
- Smaller doses of synthetic ACTH, as low as 1 mcg, have been used which may be more physiological
- In order to perform the ACTH stimulation test in an acute situation e.g. acute adrenal crises, the patient should be switched to dexamethasone and the test performed 24-36 hours later
- Avoid in ICU patients or those who are severely unwell.
- Avoid post pituitary surgery for 6 weeks or with pituitary apoplexy.
- Discuss with endocrinology if hypoadrenalism suspected.
- A cortisol of = 420nmol/L at 30 minutes post dose is an adequate adrenal response.
- Normal if the rise in plasma cortisol concentration increases by 170-200 nmol/litre (70 micrograms/litre)
- Use local laboratory lab references