: 
Test Description
The ACTH (adrenocorticotropic hormone) stimulation test is a diagnostic procedure that evaluates how well the adrenal glands respond to ACTH.
This hormone, produced by the pituitary gland, stimulates the adrenal glands to produce cortisol, a vital hormone involved in stress response and metabolism.
The test involves measuring cortisol levels in the blood before and after an injection of synthetic ACTH (cosyntropin).
This test measures how well the adrenal glands respond to ACTH, which is secreted by the pituitary gland and stimulates cortisol production in the adrenal cortex.
Purpose of the ACTH Test
The primary indications for conducting the ACTH stimulation test include:
- Diagnosis of Adrenal Insufficiency: It helps determine if the adrenal glands are producing adequate cortisol levels, which can indicate conditions like Addison’s disease or secondary adrenal insufficiency due to pituitary dysfunction.
- Evaluation of Cushing’s Syndrome: The test can also assist in diagnosing conditions associated with excessive cortisol production.
- Assessment of Pituitary Function: It evaluates whether the pituitary gland is functioning properly in its role of producing ACTH.
- Addison’s Disease: A condition where the adrenal glands do not produce sufficient cortisol.
- Hypopituitarism: A disorder where the pituitary gland fails to produce adequate hormones, including ACTH.
- Cushing’s Syndrome: A condition characterized by excessive cortisol production, which may require further evaluation.
Procedure
- Preparation: Patients are typically advised to fast for 6 to 8 hours before the test. It’s important to inform healthcare providers about any medications being taken, especially steroids, which may affect cortisol levels.
- Initial Blood Draw: A baseline blood sample is collected to measure initial cortisol levels.
- ACTH Administration: A synthetic form of ACTH (cosyntropin) is injected intramuscularly.
- Follow-Up Blood Draws: Blood samples are taken at intervals (usually 30 and 60 minutes post-injection) to measure cortisol levels and assess the adrenal response.
Patient Preparation/Instructions
To ensure accurate results, patients may need to follow these preparation guidelines:
- Fasting: It is generally recommended to fast for at least 6 hours before the test. Water is usually allowed, but caffeine or other caloric beverages should be avoided.
- Medication Review: Inform your healthcare provider about all medications you are taking, as some (e.g., steroids) may need to be paused prior to testing.
- Timing: The test is best performed in the morning before 10 AM when cortisol levels are naturally higher.
Typical Reference Values
After administering ACTH, a normal response would show an increase in cortisol levels. Typically:
- Cortisol levels should rise above 13 to 14 mcg/dL (358 to 386 nmol/L) within 30 to 60 minutes post-injection.
- Results can vary slightly depending on laboratory standards and specific testing methods.
- Normal Response: Cortisol levels should increase above 13 to 14 mcg/dL (358 to 386 nmol/L) within one hour after administration of ACTH
- Abnormal Results: Low cortisol levels post-stimulation may indicate adrenal insufficiency, while excessively high levels could suggest Cushing’s syndrome.
Risks and Considerations
The ACTH stimulation test is generally safe, but some risks associated with blood draws include:
- Lightheadedness or fainting
- Hematoma (bruising)
- Infection at the injection site
These risks are minimal and typically resolve quickly.
Turnaround Time
Results from the ACTH stimulation test are usually available within 1 to 2 weeks after the procedure.
How To Order This Test
To proceed with the ACTH stimulation test in Kenya, please click the ‘Order Test’ button and add it to your cart.
