Standard Synacthen Test

Standard Synacthen test, also known as the ACTH stimulation test or cosyntropin stimulation test, is a medical procedure used to assess the function of the adrenal glands, particularly their ability to produce cortisol. Here's how the test typically works:

1. Preparation: Before the test, the patient may be instructed to fast overnight and avoid certain medications that could interfere with the results. It's crucial to inform the healthcare provider about any medications the patient is taking.
2. Baseline Measurements: Initially, baseline measurements of cortisol levels are taken from blood samples.
3. Synacthen Administration: The patient is then given a synthetic form of adrenocorticotropic hormone (ACTH) called Synacthen, cosyntropin or acton prolangtum, typically through an injection. ACTH is a hormone produced by the pituitary gland that stimulates the adrenal glands to produce cortisol. Synacthen acts similarly to natural ACTH and stimulates the adrenal glands to produce cortisol.
4. Monitoring: Blood samples are taken at regular intervals, usually at 30 minutes and 60 minutes after Synacthen administration, to measure cortisol levels in response to the stimulation.
5. Interpretation: The results of the test are interpreted based on the cortisol response to Synacthen stimulation. Normally, cortisol levels should rise in response to the administration of Synacthen. A blunted or absent cortisol response may indicate adrenal insufficiency.

The standard Synacthen test is commonly used in the diagnosis of adrenal insufficiency, including both primary adrenal insufficiency (Addison's disease) and secondary adrenal insufficiency (due to dysfunction of the pituitary gland or hypothalamus). It helps to differentiate between primary and secondary causes of adrenal insufficiency and guides appropriate treatment.