Serum ACTH Test

The Serum ACTH test measures the level of adrenocorticotropic hormone (ACTH) in your blood. It helps doctors check how well your pituitary gland and adrenal glands are working, especially when symptoms suggest a hormone imbalance.

Because ACTH is the hormone that tells your adrenal glands to release cortisol, this test is almost always read together with a cortisol test. On its own, a single ACTH value can point in the wrong direction — the two results, plus your symptoms, form the real picture.

What Is the Serum ACTH Test?

ACTH is produced by the pituitary gland, a small pea-sized structure at the base of the brain. Its job is to signal the adrenal glands, which sit on top of each kidney, to make cortisol. Cortisol affects blood pressure, blood sugar, immunity, and the body’s response to stress.

The Serum ACTH test is a simple blood test — not a scan — that measures how much ACTH is circulating in your bloodstream. Results are reported in picograms per milliliter (pg/mL) or picomoles per liter (pmol/L), depending on the laboratory. Because ACTH follows a daily rhythm (highest in the early morning, lowest late at night), the time of the blood draw changes how the result should be read.

Why Would a Doctor Order This Test?

Doctors order this test when they suspect a problem in the pituitary–adrenal axis. Common reasons include:

• Suspected Cushing’s syndrome: unexplained weight gain, round face, easy bruising, high blood pressure, or poor blood sugar control.
• Suspected Addison’s disease (primary adrenal insufficiency): severe fatigue, low blood pressure, skin darkening, salt craving, or unintentional weight loss.
• Abnormal cortisol results from an earlier test that need further explanation.
• A possible pituitary tumor that may be producing too much ACTH.
• Monitoring during treatment for a known adrenal or pituitary condition.

The test is never used alone. It is part of a broader evaluation that includes cortisol measurement, clinical examination, and, if needed, imaging of the pituitary or adrenal glands.

How Should You Prepare for the Test?

Preparation is usually simple, but the timing matters:

• Morning appointment: the blood sample is typically taken between 8:00 and 10:00 AM, when ACTH levels are highest.
• Fasting: your doctor or the lab may ask you to fast overnight — confirm this beforehand.
• Avoid stress and heavy exercise before the draw, because both can raise ACTH temporarily.
• List your medicines: steroids (such as prednisolone or dexamethasone), birth control pills, and some other drugs can change ACTH levels.
• Tell the lab about special situations such as pregnancy, as hormone levels shift naturally.

Risks are the same as for any routine blood test: mild pain, bruising at the needle site, or rarely infection. The sample for ACTH needs chilled, rapid handling, so it is best drawn at a lab that runs this test regularly.

What Do the Results Mean?

Reference ranges vary between laboratories and with the time of day. Many labs use a morning reference range of roughly 10–60 pg/mL, but you should interpret your result against the range printed on your own lab report.

The combinations below are what your doctor looks for:

These are patterns, not final diagnoses. Doctors often follow up with dynamic tests such as the CRH stimulation test, dexamethasone suppression, or an MRI of the pituitary gland. Do not try to interpret the numbers alone — many medications and illnesses can shift ACTH in either direction.

How Is the Serum ACTH Test Different from a Cortisol Test?

ACTH and cortisol sit in the same control loop, but they answer different questions. ACTH comes from the pituitary and asks the adrenals to work; cortisol is the final hormone that affects your body. Measuring both tells the doctor whether the problem is in the pituitary, the adrenals, or both.

Availability and Cost in Bangladesh

The Serum ACTH test is available at major private diagnostic centers and hospital laboratories across Bangladesh, including Popular Diagnostic, Ibn Sina, and Square’s diagnostic services, among others in Dhaka and divisional cities. It is a specialized immunoassay, so smaller labs may send the sample to a central facility — which can affect turnaround time. A doctor’s referral is usually required.

Prices vary by city, laboratory quality, and package deals, and they change over time — always confirm the current rate before giving a sample.

Find Endocrinologist Doctors by Division in Bangladesh

If your symptoms or test results point toward a hormone disorder, the next step is a consultation with an endocrinologist. Find specialists by division:

When to See an Endocrinologist

Book an appointment with an endocrinologist if you have any of the following:

• Abnormal ACTH or cortisol results
• Unexplained weight gain or weight loss
• Persistent fatigue, muscle weakness, low blood pressure, or fainting
• High blood pressure or diabetes that is hard to control
• Skin darkening, easy bruising, or purple stretch marks

An endocrinologist can arrange the right dynamic tests, interpret the whole picture, and decide whether imaging is needed. Never start, stop, or change a steroid medicine on your own — sudden changes can be dangerous. Take your lab reports and a list of current medications to the consultation.

Frequently Asked Questions

Do I need to fast before a Serum ACTH test?

Most doctors recommend fasting for 8–12 hours before the test, but the most important factor is the time of day. ACTH levels naturally peak early in the morning (around 6–8 AM), so the sample is usually taken at that time. Always follow your doctor’s specific instructions, as certain medications or stress can affect the result.

What symptoms might lead a doctor to order this test?

Common signs include unexplained weight gain or loss, severe fatigue, muscle weakness, high blood pressure, darkening of the skin, or changes in body hair distribution. These can point to either too much cortisol (Cushing’s syndrome) or too little (adrenal insufficiency). The ACTH test helps narrow down whether the problem lies in the pituitary gland or the adrenal glands.

How long does it take to get the results in Bangladesh?

In major city labs (Dhaka, Chattogram), results are usually available within 24–48 hours. Some high-volume diagnostic centers may offer same-day reporting if the sample is collected early. In smaller cities or rural areas, samples are often sent to central labs, which can take 2–3 days. Confirm the turnaround time with the lab when you book the test.

Can the Serum ACTH test be done during pregnancy?

Yes, but interpretation is more complex. ACTH and cortisol levels naturally rise during pregnancy, especially in the third trimester. The reference ranges used for non-pregnant adults do not apply. If you are pregnant and have symptoms like severe hypertension or unusual swelling, your endocrinologist will interpret the test alongside pregnancy-specific cortisol norms.

Is the Serum ACTH test covered by health insurance in Bangladesh?

Coverage varies by insurer and policy. Many corporate health plans in Bangladesh include diagnostic tests, but ACTH is a specialized hormone assay and may require prior authorization. It is best to check with your insurance provider directly. If paying out-of-pocket, the cost typically ranges from BDT 1,500 to 3,500 depending on the lab and city.

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)