Adrenocorticotropic Hormone (ACTH)

Why is this test performed?

1. This hormone test is evaluated in different conditions, such as Adrenal insufficiency, in Acromegaly and Cushing Syndrome.
2. In Addison's disease, the level of Adrenocorticotropic hormone (ACTH) is noted more than 1000 pg/ml.
3. In Adrenal carcinoma, Adenoma, and Adrenocortical insufficiency, the level of Adrenocorticotropic hormone (ACTH) decreases.

Collection of Sample

For the estimation of Adrenocorticotropic hormone (ACTH), patient’s plasma is needed. Blood is collected in a chilled plastic test tube containing EDTA or heparin and blood is placed in cold ice-water.

The sample is centrifuged at 4º C, plasma is separated and stored at -20º C immediately within 15 minutes of the blood collection.

See: Uses of anticoagulants for hematological investigations

Note: For the diagnosis of Cushing Syndrome, the blood sample is collected in between 6 PM to 11 PM.

See: Procedures for the collection of blood for hematological investigations

Precautions

1. Collect the blood sample in a chilled plastic test tube containing EDTA or heparin.
2. Avoid high carbohydrates diet, take the low-carb diet.
3. Avoid physical activity for 12 hours before the collection of the blood sample.
4. Stop medication such as corticosteroids, 48 hours before the collection of blood sample.
5. An anxious collection of the blood sample may increase the level of Adrenocorticotropic hormone (ACTH).

Normal Values

• 6 to 8 AM: < 80 pg/ml or < 18 pmol/L (SI units)
  6 to 11 MP: < 50 pg/ml or < 11 pmol/L (SI units)
  or less than 120 pg/ml
• According to another references:
  8 AM:  < 120 pg/mL
  4 to 8 PM: < 85 pg/mL
  Cord blood: 50 to 570 pg/mL
  Newborn: 10 to 185 pg/mL

Reasons for the increased level of ACTH

1. Cushing syndrome
2. Addison's disease
3. Stress
4. Ectopic ACTH syndrome

Reasons for the decreased level of ACTH

1. Secondary adrenal insufficiency
2. Exogenous steroid administration
3. Hypopituitarism
4. Adrenal adenoma or carcinoma

The significance of Adrenocorticotropic hormone (ACTH) test for the layman

1. This test is advised in abnormal metabolism of lipids.
2. This test is advised to the patients of Diabetes Mellitus (DM).
3. This test is performed for the diagnosis of Cushing syndrome.
4. This test is advised if there are truncal obesity and thin extremity.