ACTH, Plasma

The ACTH, Plasma test contains 1 test with 1 biomarker.

Brief Description: The ACTH (Adrenocorticotropic Hormone) test measures the level of ACTH in the blood. ACTH is a hormone produced by the pituitary gland in the brain. Its primary function is to stimulate the production and release of cortisol from the adrenal glands, which are small glands located on top of the kidneys. Cortisol is a hormone that plays a crucial role in the body's response to stress, metabolism, immune function, and blood pressure regulation.

Also Known As: Adrenocorticotropic Hormone Test, Corticotropin Test, Cosyntropin Test

Collection Method: Blood Draw

Specimen Type: Plasma

Test Preparation: Collect specimen between 7 a.m. and 10 a.m. If drawn at any other time, the reference ranges do not apply

When is an ACTH test ordered?

When a cortisol test reveals aberrant results or when someone has indications or symptoms of excess or inadequate cortisol, an ACTH test may be recommended.

Cortisol excess can induce the following symptoms:

• Obesity
• Fat between the shoulders
• Red, rounded face
• Skin that is fragile and thin
• Purple lines on the abdomen
• Muscle loss
• Acne
• Skin problems
• Excessive body hair
• Fatigue

High blood pressure, low potassium, high bicarbonate, high glucose levels, and occasionally diabetes are all common with these symptoms.

People with low cortisol levels may have symptoms such as:

• Muscle wasting
• Fatigue
• Loss of weight
• Skin pigmentation increases, even in places not exposed to the sun
• Appetite loss
• Nausea, vomiting, and diarrhea
• Dizziness
• Cravings for salt

Low blood pressure, low blood glucose, low sodium, high potassium, and high calcium are frequently found in conjunction with these symptoms.

Several of the following symptoms are commonly associated with hypopituitarism:

• Appetite loss
• Fatigue
• Menstrual cycle irregularity
• Sexual organ dysfunction
• Reduced sexual desire
• Urination during the night
• Unprecedented weight loss
• Hot flashes
• sensitivity to cold

When a pituitary tumor causes symptoms, the affected person may also experience symptoms related to the compression of adjacent cells and nerves. The tumor, for example, can modify the pattern of headaches. It can also impair the nerves that control vision, creating symptoms like "tunnel vision," localized visual loss, or "double vision."

What does an ACTH blood test check for?

Adrenocorticotropic hormone is a hormone that promotes cortisol production. Cortisol is a steroid hormone produced by the adrenal glands that regulates glucose, protein, and lipid metabolism, suppresses the immune system's reaction, and aids in blood pressure regulation. This test determines how much ACTH is present in the blood.

The pituitary gland is responsible for producing ACTH. The pituitary gland is a network of glands that work together to create hormones that operate on organs, tissues, and other glands to govern systems throughout the body. It is located below the brain in the center of the head.

ACTH levels rise when cortisol levels are low and fall when cortisol levels are high. The hypothalamus produces corticotropin-releasing hormone in response to a drop in blood cortisol levels. This causes the pituitary gland to produce ACTH, which in turn stimulates the adrenal glands, which are small organs at the top of each kidney, to produce cortisol. The brain, pituitary, and adrenal glands must all be operating properly in order to produce enough levels of cortisol.

Conditions affecting the hypothalamus, pituitary, or adrenal glands can disrupt the regulation of ACTH and cortisol production, causing the glands to generate more or less of the hormones. This can result in signs and symptoms linked with cortisol excess or insufficiency. Cushing disease, Addison disease, and hypopituitarism are all conditions that impact ACTH. Some tumors outside of the pituitary, such as those in the lungs, can also produce ACTH, which raises cortisol levels.

Lab tests often ordered with an ACTH test:

When an ACTH test is ordered, it's often part of a broader evaluation of the endocrine system, particularly the hypothalamic-pituitary-adrenal (HPA) axis. Here are some tests commonly ordered alongside it:

1. Cortisol Test:

   • Purpose: To measure the level of cortisol in the blood.
   • Why Is It Ordered: To assess adrenal gland function and the HPA axis response, as ACTH stimulates the adrenal glands to produce cortisol.

2. 24-Hour Urine Cortisol:

   • Purpose: To measure the amount of cortisol excreted in the urine over 24 hours.
   • Why Is It Ordered: To provide an indication of cortisol production over a longer period, which can be more reflective of overall cortisol secretion.

3. Plasma Renin Activity and Aldosterone:

   • Purpose: To evaluate the renin-angiotensin-aldosterone system, which helps regulate blood pressure.
   • Why Is It Ordered: To assess for conditions like adrenal insufficiency or Conn’s syndrome, which can affect electrolyte balance and blood pressure.

4. Blood Electrolytes:

   • Purpose: To measure key electrolytes in the blood.
   • Why Is It Ordered: Electrolyte imbalances can be a sign of adrenal dysfunction, as cortisol and aldosterone regulate sodium and potassium levels.

5. Insulin-like Growth Factor-1 (IGF-1):

   • Purpose: To measure the level of IGF-1, which is influenced by growth hormone (GH).
   • Why Is It Ordered: To assess pituitary function, as ACTH production can be related to other pituitary hormones.

6. Prolactin:

   • Purpose: To measure the level of prolactin, another hormone produced by the pituitary gland.
   • Why Is It Ordered: To evaluate pituitary gland function and rule out pituitary disorders that can affect multiple hormones.

7. Thyroid Function Test:

   • Purpose: To assess thyroid function.
   • Why Is It Ordered: To rule out or diagnose thyroid disorders, as pituitary and thyroid functions are interconnected.

These tests, when ordered alongside an ACTH test, provide a comprehensive view of an individual’s endocrine system, particularly the HPA axis. They are crucial for diagnosing, managing, and monitoring conditions like Cushing's syndrome, Addison's disease, and other disorders affecting the adrenal or pituitary glands. The specific combination of tests will depend on the individual’s symptoms, medical history, and the results of initial screenings.

Conditions where an ACTH test is recommended:

The ACTH test is essential in diagnosing and monitoring various conditions, including:

1. Adrenal Insufficiency (Addison's Disease): In Addison's disease, the adrenal glands do not produce enough cortisol, often due to a problem with the adrenal glands themselves or inadequate ACTH production.

2. Cushing's Syndrome: In Cushing's syndrome, excessive cortisol production can result from a pituitary tumor (Cushing's disease) or adrenal tumors.

3. Pituitary Disorders: Tumors or dysfunctions affecting the pituitary gland can disrupt ACTH production and lead to hormonal imbalances.

4. Hypothalamic Disorders: Conditions affecting the hypothalamus can also impact ACTH secretion.

How does my health care provider use an ACTH test?

ACTH blood tests are used to detect, diagnose, and monitor problems related with excessive or deficient cortisol in the body, usually in conjunction with cortisol tests. These circumstances include:

• Cushing disease is characterized by high cortisol levels caused by an ACTH-producing tumor in the pituitary gland.
• Cushing syndrome refers to the symptoms and signs of high cortisol levels; it can be caused by an adrenal tumor, adrenal hyperplasia, steroid use, or an ACTH-producing tumor outside the pituitary, such as in the lungs.
• Cortisol production is reduced in Addison disease due to adrenal gland injury.
• Secondary adrenal insufficiency: pituitary dysfunction causes decreased cortisol production.
• Hypopituitarism is pituitary dysfunction or injury that causes the pituitary to produce less hormones, notably ACTH.

Because the level of ACTH generally varies in the opposite direction of the level of cortisol, measuring both can assist distinguish between some of these diseases.

If abnormal levels are found, a healthcare professional will do additional testing to confirm the results and discover the cause.

What do my ACTH test results mean?

The interpretation of the results can be difficult in many circumstances. ACTH and cortisol levels fluctuate throughout the day. ACTH levels are normally highest in the morning and lowest at night. It will increase cortisol production, which will follow the same daily rhythm as ACTH but rise later in the day and fall later in the evening. This diurnal rhythm is frequently disrupted by conditions that influence ACTH and cortisol synthesis.

ACTH and cortisol patterns associated with various illnesses of the adrenal and pituitary glands.

An adrenal tumor, steroid treatment, or hypopituitarism can all cause a reduction in ACTH.

Cushing disease and ectopic ACTH cannot be reliably distinguished from cortisol and ACTH measurements alone. Other tests are also performed to aid healthcare providers in determining this distinction. When some medications are given to promote or repress hormone synthesis, testing the change in cortisol levels might assist the healthcare practitioner establish the correct diagnosis.

Most Common Questions About the ACTH test:

Understanding the ACTH Test

What is the ACTH test?

The Adrenocorticotropic Hormone (ACTH) test measures the level of ACTH in the blood. ACTH is a hormone produced by the pituitary gland that stimulates the adrenal glands to release cortisol, a hormone that helps the body respond to stress.

Why is the ACTH test important?

The ACTH test is crucial because it can help diagnose conditions associated with too much or too little cortisol in the body, such as Cushing's syndrome, Addison's disease, and hypopituitarism.

When is an ACTH test recommended?

An ACTH test is typically recommended when a person has symptoms suggestive of conditions that affect cortisol levels. Symptoms may include weight gain, fatigue, muscle weakness, low blood pressure, or skin changes.

Can the ACTH test diagnose specific diseases?

The ACTH test is used as a part of the process to diagnose diseases related to the pituitary and adrenal glands, like Addison's disease, Cushing's syndrome, and secondary adrenal insufficiency.

Interpreting ACTH Test Results

What does a high level of ACTH indicate in the test?

High ACTH levels can indicate conditions like Addison's disease, Cushing's disease, or ectopic ACTH-producing tumors.

What does a low level of ACTH indicate in the test?

Low ACTH levels can indicate conditions like secondary adrenal insufficiency or Cushing's syndrome due to an adrenal tumor or steroid medication overuse.

How are ACTH levels affected by stress?

Stress can stimulate ACTH production as part of the body's "fight or flight" response. This, in turn, leads to increased cortisol production to manage the stressful situation.

How can ACTH test results help differentiate between different diseases?

The ACTH test, often coupled with a cortisol test, can help differentiate between primary and secondary adrenal insufficiency. High ACTH with low cortisol suggests primary adrenal insufficiency (Addison's disease), while low ACTH with low cortisol suggests secondary adrenal insufficiency.

ACTH Test and Specific Conditions

How does the ACTH test relate to Cushing's syndrome?

The ACTH test can help differentiate between types of Cushing's syndrome. High ACTH levels suggest Cushing's disease (pituitary cause), while low ACTH levels suggest an adrenal or ectopic cause.

How does the ACTH test relate to Addison's disease?

Addison's disease, or primary adrenal insufficiency, leads to a decrease in cortisol production. The pituitary responds by increasing ACTH production, leading to high ACTH levels in this condition.

Can the ACTH test help in diagnosing hypopituitarism?

Yes, low ACTH levels can suggest hypopituitarism, a condition where the pituitary gland does not produce sufficient hormones, including ACTH.

How is the ACTH test used in the diagnosis and management of adrenal insufficiency?

The ACTH test is used to diagnose both primary and secondary adrenal insufficiency by looking at ACTH levels in conjunction with cortisol levels. It can also help in monitoring the effectiveness of treatment.

General Questions About the ACTH Test

Can medications affect the ACTH test results?

Yes, certain medications like corticosteroids, estrogen, and anti-seizure drugs can affect ACTH levels and hence the test results.

What is an ACTH stimulation test?

An ACTH stimulation test is a different test where synthetic ACTH is given and cortisol response is measured. It's used to diagnose adrenal insufficiency and assess the adrenal glands' function.

What other tests are usually done along with the ACTH test?

Typically, cortisol levels are also measured along with ACTH. In some cases, other tests like the ACTH stimulation test or dexamethasone suppression test may be performed.

Can an ACTH test be used to monitor the treatment of Addison's disease?

Yes, the ACTH test, along with cortisol test, can be used to monitor the effectiveness of treatment in Addison's disease.

Can one have normal ACTH and abnormal cortisol levels?

Yes, this can happen. For instance, in adrenal tumors causing Cushing's syndrome, cortisol levels are high, but ACTH levels can be low due to negative feedback inhibition.

Can the ACTH test be used in the diagnosis of pituitary tumors?

Yes, if a pituitary tumor is producing ACTH, the ACTH test, along with cortisol and imaging studies, can aid in diagnosis.

Can ACTH levels change during pregnancy?

Yes, ACTH levels can increase during pregnancy. This is a normal physiological response and helps in the increased production of cortisol necessary during pregnancy.

What role does the ACTH test play in the diagnosis of congenital adrenal hyperplasia?

Congenital adrenal hyperplasia, a genetic disorder affecting cortisol production, can lead to increased ACTH levels. The ACTH test can aid in diagnosis, especially when coupled with other hormonal tests.

Can the ACTH test be used in the diagnosis of depression or chronic fatigue syndrome?

While the ACTH test is not used to diagnose these conditions, research suggests alterations in the HPA (hypothalamus-pituitary-adrenal) axis, involving ACTH, in conditions like depression and chronic fatigue syndrome.

How does the ACTH test relate to the diagnosis of ectopic ACTH syndrome?

Ectopic ACTH syndrome is a condition where ACTH is produced by non-pituitary tumors, leading to high ACTH and cortisol levels. The ACTH test can aid in diagnosis and management.

Can the ACTH test be used to diagnose stress-related disorders?

While the ACTH test is not typically used to diagnose stress disorders, research suggests a role of the HPA axis, involving ACTH, in stress response. It's used primarily to diagnose endocrine disorders.

Can the ACTH test be used to monitor the effectiveness of treatment in Cushing's syndrome?

Yes, the ACTH test can help monitor the response to treatment in Cushing's syndrome, along with cortisol levels.

Can the ACTH test help in the diagnosis of Nelson's syndrome?

Nelson's syndrome is a rare condition that can occur in patients who have had their adrenal glands removed for Cushing's disease. These patients can develop ACTH-producing pituitary tumors leading to high ACTH levels, which can be identified by the ACTH test.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.