Short Synacthen Test

The Synacthen test is an essential diagnostic method used when adrenal insufficiency or congenital adrenal hyperplasia is suspected. This test assesses whether the adrenal glands respond adequately to stimulation by adrenocorticotropic hormone (ACTH), which is a crucial step in establishing an accurate diagnosis and initiating timely treatment.

Why is the Synacthen test performed?

The adrenal glands are responsible for producing several important hormones:

• Mineralocorticoids help maintain the body’s salt and fluid balance, as well as stable blood pressure;
• Glucocorticoids regulate metabolic processes, help the body respond to stress, and act as anti-inflammatory agents;
• Androgens contribute to sexual development and the formation of secondary sexual characteristics.

The secretion of these hormones is regulated by ACTH, which is produced in the brain. If ACTH levels are insufficient or the adrenal glands do not respond to it, a hormonal deficiency can occur in the body. The Synacthen test helps determine whether the disorder originates at the brain level (due to a lack of ACTH) or within the adrenal glands themselves.

How is the examination performed?

During the test, Synacthen, a synthetic analogue of ACTH, is injected into a vein to stimulate the release of adrenal hormones. Blood samples are taken before the injection and again (usually after 30 and 60 minutes) to measure cortisol levels and, if necessary, 17-hydroxyprogesterone levels. If hormone levels do not increase significantly, this indicates adrenal insufficiency. On the other hand, a sharp rise in 17-hydroxyprogesterone levels may suggest adrenal hyperplasia.

Preparation for the test

The patient may eat and drink as usual; however:

• Hormonal medications must be discontinued at least 6 weeks before the test;
• If the patient is taking hydrocortisone, dosage adjustments are determined by the treating physician;
• Oral contraceptives should be discontinued at least 6 weeks prior to the examination;
• The test is performed in the morning hours (approximately between 8:00 and 9:00 a.m.);
• Before the test, a catheter is inserted into a vein for medication administration and blood sample collection.

Possible risks

The Synacthen test is generally safe and well tolerated. In rare cases, an allergic reaction to Synacthen may occur, especially in patients with severe allergies. Our medical team is always prepared to provide professional assistance immediately.