Short Synacthen Stimulation Test
Tetracosactrin (Synacthen, Cortrosyn) is a synthetic preparation
comprising the first 24 amino acids of ACTH. It stimulates the
adrenal cortex to produce cortisol, failure to respond indicating
impaired adrenocortical function.
This test is of value in patients with suspected adrenocortical
insufficiency eg. Addison's disease and also during the later
stages of withdrawal and following total cessation of previous
long-term high dose glucocorticoid drug therapy, including topical
This test can be used either as an in-patient or out-patient
If results are required daily then the appropriate
arrangements must be made with the Clinical Biochemistry
Please refer to the Trust's phlebotomy procedure for sample
Caution: withdrawal of glucocorticoids may be
dangerous. (Pharmacological doses of glucocorticoids should
not have been administered for the previous 12 hours prior to the
Allergic reactions to tetracosactrin are a possibility, but
This test is best performed early in the morning. The patient is
placed in a reclining position to rest for 30 minutes prior to the
test. Smoking is not permitted. Pharmacological doses of
glucocorticoids should not have been administered for the previous
Take basal venous blood sample (6ml SST tube - yellow top).
250ug of Tetracosactrin dissolved in about 1ml of sterile
water or isotonic saline is administered intramuscularly.
(Tetracosactrin is marketed as Synacthen (Ciba) for Cortrosyn
After 30 minutes a further blood sample is taken (6ml
SST tube - yellow top).
Label the samples with patient details and actual time taken.
When test is complete, send request form and samples to the
Clinical Biochemistry Department as soon as possible.
Normal response: The 30 minutes sample should show a
cortisol level >600 nmol/l.
Failure to meet the normal criteria indicates adrenocortical
insufficiency due to any cause. Low normal levels or partial
responses are compatible with some degree of adrenocortical
impairment and are an indication for further investigation ie.
5 day Tetracosactrin stimulation test. A clearly normal
response excludes primary and secondary adrenocortical
insufficiency and indicates that further tests are not