✍️ Written by the MedTestBD Editorial Team · Last reviewed: July 2026
What is the ACTH Stimulation Test?
The ACTH Stimulation Test (also called the Short Synacthen Test or SST) evaluates how well the adrenal glands respond to ACTH stimulation. A synthetic form of ACTH (synacthen) is injected, and cortisol levels are measured before and after the injection. Healthy adrenal glands respond by producing a significant rise in cortisol. If the rise is inadequate, it confirms adrenal insufficiency — the inability of the adrenal glands to produce enough cortisol when the body demands it.
Why is the ACTH Stimulation Test Done?
- To confirm adrenal insufficiency — both primary (Addison's disease) and secondary (pituitary failure)
- To investigate unexplained fatigue, weight loss, low blood pressure, dizziness, or salt craving
- To assess adrenal gland function in patients who have been on long-term steroid therapy — steroids suppress the adrenal glands and cause secondary adrenal insufficiency
- To evaluate suspected adrenal crisis in critically ill patients
- More definitive than a single basal cortisol measurement for diagnosing adrenal insufficiency
Normal ACTH Stimulation Test Results
| Measurement | Normal Response |
|---|---|
| Basal cortisol (before injection) | Above 170 nmol/L (6 µg/dL) |
| Peak cortisol (30–60 min after injection) | Above 500 nmol/L (18 µg/dL) |
| Rise from baseline | Increase of at least 200 nmol/L |
A peak cortisol above 500 nmol/L (18 µg/dL) after stimulation confirms adequate adrenal function. A peak below this threshold confirms adrenal insufficiency. Some labs use slightly different cut-offs — your endocrinologist will interpret results using the reference ranges specific to their laboratory assay.
How to Prepare for the ACTH Stimulation Test
- The test is usually done in the morning — fasting overnight may be required depending on your doctor's instructions
- Inform your doctor about any steroid medications you take — hydrocortisone, prednisolone, and dexamethasone interfere with cortisol measurement and must be paused as directed
- Oral contraceptives raise cortisol-binding protein and may affect results — inform your doctor
- The test involves a blood draw, a synacthen injection, and one or two further blood draws at 30 and 60 minutes — allow approximately 90 minutes for the full procedure
- The injection itself is safe and well tolerated; mild flushing is occasionally reported
ACTH Stimulation Test Price in Bangladesh
ACTH stimulation test prices vary between diagnostic centers across Bangladesh. Compare ACTH stimulation test prices on MedTestBD →
⚠️ This information is for general reference only. Always consult a qualified physician before undergoing any medical test.
