What is ACTH?
Adenocorticotropic hormone (ACTH) is produced by the anterior pituitary gland. It plays a vital role in regulating cortisol, which is involved in stress management, immune response and metabolism. ACTH is also responsible for stimulating the production of aldosterone and androgens by adrenal glands. It is also used as a medicine and as a diagnostic agent.
The ACTH test accurately measures the ACTH hormone in the bloodstream. It is beneficial in diagnosing several conditions related to cortisol imbalance, including Cushing’s syndrome, hypopituitarism, Addison’s disease, and secondary adrenal insufficiency.
How is the Test Performed?
A simple blood draw is performed for the ACTH Test and then analyzed in the laboratory. When peak levels of ACTH need to be monitored the healthcare provider instructs to get the test done in the morning, whereas the test will be performed in the evening if low ACTH trough is required.
Preparation
- Fasting of 6-8 hours is usually required prior to the test
- Certain medications will be advised to be avoided by the healthcare provider
- Avoid excessive exercise before the test.
- Avoid emotional stress for at least 12-16 hours before the test.
- Eat low-carbohydrate food 48 hours before the test
Blood Draw
- The process is called venipuncture and involves the withdrawal of blood from the vein of the arm.
- The sample is then placed in a special tube for further analysis.
Laboratory Analysis
The sample is sent to the laboratory for the analysis of ACTH using a chemiluminescence assay for precise results.
What are the symptoms that prompt this test?
ACTH test is recommended if signs and symptoms of adrenal and pituitary gland dysfunction are visible in patients. Children and adults show different symptoms. The common symptoms seen are mentioned below;
Symptoms in Children
- Delay in growth
- Nausea and vomiting
- Weight loss
- High susceptibility to infections
- Fatigue and weakness
- Symptoms in Adults
- Salt-cravings
- Low blood pressure and dizziness
- Changes in skin conditions such as darkening
- Easy bruising
- Anxiety, depression and irritability
- Thin skin with stretch marks
- Easily breaking bones
- Confusion
- Severe fatigue
- Diarrhea
What are Normal Ranges for This Test?
ACTH levels vary based on the test timing, ACTH levels are elevated in the morning and lowered in the evening, Stress, trauma, menstruation, and pregnancy. Normal ranges vary according to the assay used as well;
Adults (morning) – 10-60 picograms/L
Adults (evening) – 20 picograms/L
Children (morning) – 9-52 picograms/L
**The values above are general guidelines only and vary according to the laboratory’s reference ranges and methodology. **
What Happens if Test Results Show Abnormal Levels?
Abnormal levels of ACTH indicate an underlying condition according to the elevation or decreased levels.
High ACTH Indicate
- Cushing’s disease caused due to a tumor in the pituitary gland that overproduces ACTH level.
- Ectopic ACTH Syndrome
- Addison’s disease
Low ACTH Indicate
- Secondary Adrenal Insufficiency.
- Cushing’s Syndrome
- Medications such as glucocorticoids
- Pituitary tumors
If abnormalities are diagnosed further testing is suggested for timely management of the underlying conditions to normalize ACTH levels.
