The ACTH stim test, also known as the cosyntropin stimulation test, is a medical diagnostic test used to assess the functioning of the adrenal glands and their ability to produce cortisol. It is commonly performed to evaluate adrenal insufficiency, differentiate between primary and secondary adrenal insufficiency, and determine the integrity of the hypothalamic-pituitary-adrenal (HPA) axis.

Symptoms:

The symptoms of low cortisol include:

• Weak Muscles
• Fatigue
• Weight Loss
• Increased Skin pigmentation in areas not exposed to the sun
• A loss of appetite
• Low blood pressure
• Low blood glucose levels
• Low sodium levels
• High potassium levels
• High Calcium Levels

Why Get Tested:

If you have a high cortisol level, you may have:

• Obesity
• A rounded face
• Fragile, thin skin
• Purple lines on the abdomen
• Weak muscles
• ACNE
• An increased amount of body hair
• High Blood Pressure
• Low Potassium Levels
• High Bicarbonate Level
• High Glucose Levels
• Diabetes

Purpose Of The Test (Indications)

1. This hormone is estimated in various conditions like Adrenal insufficiency, in Cushing’s syndrome and Acromegaly, etc.
2. For the diagnosis of Addison’s disease (level is>1000 pg /ml).
3. Its level decreases in Secondary Adrenocortical Insufficiency, Adrenal carcinoma, and adenoma.
4. This is the test of the anterior pituitary gland.

Sample

1. The Patient’s plasma is needed.
   1. Place blood immediately in ice water and freeze plasma in 15 min.
2. The sample should be collected in a prechilled plastic test tube with EDTA or heparin.
3. For the diagnosis of Cushing’s syndrome, the sample should be taken between 6 to 11 pm.
4. Centrifuge the sample at 4 °C and store at -20 °C immediately within 15 minutes of collection.

Precaution

1. A stressful collection of the blood will raise the level.
2. Avoid physical activity 10 to 12 hours prior to taking the sample.
3. Stop medication like corticosteroids 48 hours before this test.
4. Collect the sample in a chilled plastic vial with EDTA or Heparin.
5. ACTH is very labile and requires antiprotease in the collecting vial.
6. In the routine, the ACTH level is not measured because it degrades in the plasma.
7. Put the patient on a low carbohydrate diet.

• Adrenocortical hormone (ACTH) is produced by the anterior pituitary lobe.
• Corticotropin-releasing-hormone (CRH) is made and released from the hypothalamus and gives rise to the release of ACTH from the pituitary glands.
• ACTH is advised for investigating disorders of the hypothalamic, pituitary and renal system.
• ACTH is secreted by the anterior pituitary gland that signals the adrenal gland to produce steroids (androgens, cortisol, and aldosterone). These are needed for the normal functioning of the body.
• With adrenal insufficiency, the pituitary gland release proopiomelanocortin and ACTH are increased.
• ACTH is unstable in the blood. Most commercial RIA kits are insensitive and nonspecific to measure ACTH.

Normal Value:

• 6 to 8 a.m = < 80 pg / mL or <18 pmol /L (SI units).
• 6 to 11 p.m = < 50 pg /mL or <11 pmol /L (SI units).
• or less than 120 pg/ml

Increased ACTH Level Is Seen In:

1. Addison disease (primary adrenal insufficiency).
2. Ectopic ACTH syndrome.
3. Cushing’s syndrome. This is dependent upon the adrenal hyperplasia due to the pituitary gland.
4. Stress.

Decreased ACTH Level Is Seen In:

1. Hypopituitarism.
2. Secondary adrenal insufficiency is due to pituitary insufficiency.
3. Adrenal adenoma or cancer.
4. Exogenous steroid administration.

Possible References Used

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