Serum ACTH Test

If your doctor has ordered a Serum ACTH Test, you likely have symptoms suggesting a problem with your adrenal glands or pituitary gland—such as unexplained weight changes, fatigue, skin darkening, or high blood pressure. This test measures the level of adrenocorticotropic hormone (ACTH) in your blood, which is the signal your pituitary gland sends to your adrenal glands to produce cortisol. Understanding what this test involves, how to prepare, and what the results might mean can help you approach it with confidence.

What does the Serum ACTH test measure?

ACTH is a hormone produced by the pituitary gland, a small gland at the base of your brain. It travels through the bloodstream to your adrenal glands (located on top of each kidney) and tells them to release cortisol—a hormone that helps regulate metabolism, inflammation, stress response, and blood pressure. The Serum ACTH Test simply measures the amount of ACTH circulating in your blood at the time of the draw. It is almost always interpreted alongside a cortisol test because the two hormones work together in what doctors call the hypothalamic-pituitary-adrenal (HPA) axis.

Why might your doctor order this test?

Your doctor may order the ACTH test to investigate conditions where the HPA axis is disrupted. Common scenarios include:

• Cushing’s syndrome: Symptoms like rapid weight gain (especially in the face and abdomen), easy bruising, and high blood pressure. The test helps determine if the cause is a pituitary tumor (Cushing disease, with high ACTH) or an adrenal tumor (low ACTH).
• Addison’s disease (primary adrenal insufficiency): Symptoms such as fatigue, darkening of the skin, weight loss, and low blood pressure. Here, ACTH is typically high because the adrenal glands are not responding.
• Secondary adrenal insufficiency: Caused by a pituitary problem (e.g., tumor, injury). ACTH levels are low, and cortisol is also low.
• Pituitary tumor evaluation: To check if an ACTH-secreting tumor is present.
• Monitoring treatment: For patients on long-term steroid therapy or after pituitary surgery.

How to prepare for the test

Preparation is straightforward, but a few points matter:

• Time of day: ACTH levels follow a natural daily rhythm (highest around 8 a.m., lowest at night). Your blood draw is usually scheduled for early morning (8–9 a.m.) unless your doctor specifies otherwise.
• No fasting required: You can eat normally. But avoid heavy meals or caffeine right before the test.
• Avoid stress: Physical or emotional stress can raise ACTH temporarily. Try to relax before the draw.
• Medications: Inform your doctor about all medications, especially steroids (prednisone, dexamethasone), birth control pills, and certain antidepressants—they can alter ACTH levels. Your doctor may ask you to temporarily stop some.
• Dynamic tests: Sometimes the ACTH test is part of a stimulation or suppression test (e.g., CRH stimulation, dexamethasone suppression). Follow your doctor’s specific instructions for these.

The procedure and critical sample handling

The test is a standard blood draw from a vein in your arm. However, ACTH is fragile—it breaks down quickly at room temperature. For accurate results, the lab must follow a strict protocol:

• Blood is drawn into a chilled EDTA tube (purple-top).
• The tube must be placed immediately on ice.
• It must be centrifuged within 15–20 minutes and the plasma frozen.

Not all labs in Bangladesh are equipped to handle this. Before booking, ask the lab: “Do you use a chilled EDTA tube and process the sample on ice?” If they cannot confirm, choose a lab that specializes in hormone testing. In Dhaka, accredited labs like Popular Diagnostics, LabAid, and Ibn Sina have the necessary setup, but always double-check.

Understanding your results

Reference ranges vary by laboratory, but typical morning ACTH levels are between 10–60 pg/mL (2.2–13.2 pmol/L). Afternoon levels are lower. The following table gives a simplified picture of how ACTH and cortisol together suggest different conditions. Do not interpret results on your own—an endocrinologist is essential.

ACTH level	Cortisol level	Possible implication
High	High	Cushing disease (pituitary tumor) or ectopic ACTH production (e.g., lung tumor)
Low	High	Adrenal tumor (Cushing syndrome)
High	Low	Primary adrenal insufficiency (Addison’s disease)
Low	Low	Secondary adrenal insufficiency (pituitary or hypothalamic cause)

Cost and availability in Bangladesh

In Bangladesh, the Serum ACTH test is available mainly in major private labs and tertiary hospitals. Prices vary by city, lab accreditation, and whether you choose a standard package or an advanced hormone panel. Below are approximate ranges—always confirm with the lab before booking.

Item	Approx. BDT range	Notes
Private lab (standard) – Dhaka, Chittagong	1,500 – 2,500	Results in 1–3 days; verify cold-chain handling
Private lab (standard) – Sylhet, Rajshahi	2,000 – 3,000	May take longer due to sample transport
Hospital/advanced lab (e.g., BIRDEM, United Hospital)	3,000 – 4,000	Often includes cortisol and faster turnaround
Dynamic test package (CRH stimulation or dexamethasone suppression)	5,000 – 8,000	Includes multiple draws and specialist interpretation

Costs change frequently and may differ by city and lab. Call ahead for the current price and to confirm that the lab follows proper cold-chain protocols.

When to see a specialist

Your primary care doctor or general practitioner may order the ACTH test as part of an initial workup. However, if your results are abnormal or if you have persistent signs like unusual weight gain, skin darkening, severe fatigue, or muscle weakness, it is wise to consult an endocrinologist—a doctor who specializes in hormone disorders. They can interpret your ACTH and cortisol results in the full context of your symptoms and design a treatment plan. In Bangladesh, you can find endocrinologists in major hospitals and diagnostic centers in Dhaka, Chittagong, and other divisions. For a list of specialists, you may use trusted directories.

Division	Find a doctor
Dhaka / ঢাকা	Best ENT Surgeon Doctors in Dhaka
Chittagong / চট্টগ্রাম	ENT Surgeon Doctors in Chattogram
Khulna / খুলনা	Recommended ENT Surgeon Doctors in Khulna
Rajshahi / রাজশাহী	ENT Surgeon Doctors in Rajshahi
Rangpur / রংপুর	Find ENT Surgeon doctors in Rangpur
Sylhet / সিলেট	Popular ENT Surgeon Doctors in Sylhet
Barishal / বরিশাল	Verified ENT Surgeon Doctors in Barishal
Mymensingh / ময়মনসিংহ	ENT Surgeons in Mymensingh

Frequently Asked Questions

Can stress or time of day affect my ACTH test results?

Yes. ACTH follows a natural daily rhythm called a circadian rhythm, peaking in the early morning (around 6–8 a.m.) and falling throughout the day. Stress, illness, pain, or intense exercise can also raise ACTH levels. That is why your doctor will schedule the test at a specific time—usually around 8 a.m.—and ask you to rest before the blood draw. Inform your doctor about any recent illness, injury, or significant emotional stress so results are interpreted correctly.

Is the Serum ACTH test safe during pregnancy?

The test itself is considered safe during pregnancy because it involves a routine blood draw. However, ACTH and cortisol levels naturally rise in pregnancy, especially in the second and third trimesters. Your doctor will use pregnancy-specific reference ranges to interpret your result. Always tell your doctor or phlebotomist if you are pregnant or think you might be, so they can take appropriate precautions and adjust the reference values.

What happens if my ACTH level is normal but cortisol is abnormal?

This pattern is clinically important. A normal ACTH with abnormal cortisol can suggest a problem with the adrenal glands directly (primary adrenal disorder) or a cyclic condition where hormone levels fluctuate. For example, in early Cushing’s disease, ACTH may be inappropriately normal while cortisol is high. Alternatively, a normal ACTH with low cortisol points toward primary adrenal insufficiency (Addison’s disease). Your doctor will usually order additional tests—such as a CRH stimulation test, ACTH stimulation test, or imaging—to pinpoint the cause.

How long does it take to get ACTH test results in Bangladesh?

Because ACTH is fragile and must be processed quickly—typically within 20–30 minutes of collection—samples are sent to specialized labs in major cities. Results are usually available within 24 to 48 hours. Some high-volume diagnostic centers in Dhaka, Chittagong, or Sylhet offer same-day results if the sample is drawn early. For samples from smaller towns, shipping to the central lab can add 1–2 days. Always ask your lab about their specific turnaround time.

Can I take my regular medications before the ACTH test?

Many medications can interfere with ACTH levels, including steroids (prednisolone, dexamethasone), oral contraceptives, some seizure medications, and insulin. Do not stop any prescribed medicine on your own. Instead, provide your doctor with a complete list of everything you take—including over-the-counter drugs, supplements, or herbal remedies—well before the test. Your doctor may ask you to temporarily stop certain medications or adjust the timing of your dose to get an accurate measurement.

Sources

The following sources are from international journals, government health agencies, or recognized medical organizations:

• ACTH Test – Mayo Clinic (mayoclinic.org)
• World Health Organization — Serum ACTH Test (who.int)
• MedlinePlus — Serum ACTH Test (medlineplus.gov)
• CDC — Serum ACTH Test (cdc.gov)
• NHS — Serum ACTH Test (nhs.uk)
• PubMed — Serum ACTH Test (pubmed.ncbi.nlm.nih.gov)