✍️ Written by the MedTestBD Editorial Team · Last reviewed: July 2026
What is the Serum ACTH Test?
The Serum ACTH (Adrenocorticotropic Hormone) test measures the level of ACTH in the blood. ACTH is produced by the pituitary gland in the brain and signals the adrenal glands to produce cortisol. By measuring ACTH alongside cortisol, doctors can determine whether an abnormal cortisol level originates from a problem in the pituitary gland, the adrenal glands, or from an external source. It is essential for diagnosing adrenal and pituitary disorders.
Why is the Serum ACTH Test Done?
- To diagnose Cushing's syndrome and identify its cause — pituitary tumour, adrenal tumour, or ectopic ACTH production
- To diagnose Addison's disease — primary adrenal insufficiency where ACTH is very high but cortisol is low
- To distinguish between primary adrenal insufficiency (high ACTH) and secondary adrenal insufficiency due to pituitary failure (low ACTH)
- To investigate unexplained fatigue, weight changes, abnormal blood pressure, or skin hyperpigmentation
- To evaluate pituitary gland function as part of a full hormonal panel
Normal Serum ACTH Levels
| Time of Test | Normal ACTH Level |
|---|---|
| Morning (8:00 AM) — peak | 10 – 60 pg/mL (2.2 – 13.3 pmol/L) |
| Evening — lower | Below 20 pg/mL |
Like cortisol, ACTH follows a diurnal rhythm — highest in the early morning and lowest at night. The ACTH-cortisol relationship is key to diagnosis: high ACTH with low cortisol suggests primary adrenal failure (Addison's disease). Low ACTH with high cortisol points to an adrenal tumour autonomously producing cortisol. High ACTH with high cortisol suggests Cushing's disease from a pituitary source.
How to Prepare for the Serum ACTH Test
- Blood is collected in the early morning around 8:00 AM — timing is critical as ACTH peaks at this time
- The sample must be collected into a chilled EDTA tube and processed immediately — ACTH degrades rapidly at room temperature
- Inform your doctor about any steroid medications you are taking — they suppress ACTH and cause false low results
- Avoid heavy exercise, stress, and caffeine before the test
- ACTH is almost always tested alongside serum cortisol for meaningful interpretation
Serum ACTH Test Price in Bangladesh
Serum ACTH test prices vary between diagnostic centers across Bangladesh. Compare serum ACTH test prices on MedTestBD →
⚠️ This information is for general reference only. Always consult a qualified physician before undergoing any medical test.
