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Adrenal insufficiency – Diagnostics

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Adrenal insufficiency is a rare but serious condition that develops when the adrenal glands cannot produce enough essential hormones, particularly cortisol. The condition often unfolds quietly, with symptoms appearing so gradually that people may dismiss them for months or even years. Understanding how doctors identify this disorder through diagnostic tests can be the difference between timely treatment and a life-threatening crisis.

Introduction: Who Should Undergo Diagnostics

Seeking diagnostic testing for adrenal insufficiency becomes important when you experience certain warning signs that persist or worsen over time. If you find yourself dealing with unexplained extreme tiredness that doesn’t improve with rest, combined with other symptoms like dizziness when standing up, unexplained weight loss, cravings for salty foods, or patches of darkened skin, it’s time to talk to your doctor about testing.[1][3]

People who have been taking glucocorticoid medications (also known as steroids) such as prednisone, hydrocortisone, or dexamethasone for three weeks or longer should be particularly alert. These medications can suppress the natural function of your adrenal glands, and stopping them suddenly could trigger a serious problem called adrenal crisis. Anyone who has used these medications regularly should discuss testing with their healthcare provider before stopping treatment.[2][10]

Individuals with certain autoimmune conditions also face higher risk and may benefit from earlier evaluation. If you have been diagnosed with Type 1 diabetes, thyroid problems like chronic thyroiditis or Graves’ disease, vitiligo (a skin condition causing loss of pigmentation), or pernicious anemia, you belong to a group that’s more likely to develop autoimmune adrenal insufficiency. The body’s immune system, which already attacks one part of the body, may also target the adrenal glands.[7][9]

Anyone experiencing symptoms of an adrenal crisis—which is a medical emergency—needs immediate medical attention rather than routine diagnostic testing. An adrenal crisis occurs when cortisol levels drop dangerously low, usually triggered by severe illness, injury, surgery, or physical stress. Signs include sudden severe pain in the lower back, belly, or legs; extreme weakness; confusion or restlessness; severe vomiting or diarrhea; very low blood pressure; and loss of consciousness. This situation requires emergency treatment first, with diagnostic confirmation following once the person is stable.[7][14]

⚠️ Important
Many people with adrenal insufficiency initially ignore their symptoms because they develop so slowly and seem vague. Fatigue, weakness, and general unwellness can be mistaken for stress, depression, or simply being “run down.” However, without proper diagnosis and treatment, this condition can progress to a life-threatening adrenal crisis. A high level of clinical suspicion is needed, and you shouldn’t hesitate to ask your doctor about testing if symptoms persist.

Doctors should also consider testing in people with pituitary gland problems. The pituitary gland is a small gland at the base of the brain that produces ACTH (adrenocorticotropic hormone), which signals the adrenal glands to make cortisol. If you’ve had a pituitary tumor, pituitary surgery, radiation treatment to the head, or a significant head injury, your pituitary may not produce enough ACTH. This leads to a form called secondary adrenal insufficiency.[1][10]

Diagnostic Methods to Identify and Distinguish Adrenal Insufficiency

Diagnosing adrenal insufficiency requires demonstrating that your body isn’t producing enough cortisol, and then determining why this is happening. The diagnostic process typically begins with a conversation between you and your doctor about your symptoms and medical history. Your doctor will ask detailed questions about when symptoms started, whether they’ve gotten worse, what medications you take, and whether you have other health conditions. This conversation helps determine whether testing is warranted and what type of testing would be most informative.[2][12]

The cornerstone of diagnosis is blood testing to measure hormone levels. Your doctor will order a test to check your cortisol level, typically in the morning when cortisol should be at its highest. If this level is very low, it suggests adrenal insufficiency. However, cortisol levels can vary throughout the day and may fall in a gray area that’s neither clearly normal nor clearly abnormal, so additional testing is usually needed to confirm the diagnosis.[2][19]

The most reliable test for confirming adrenal insufficiency is called the ACTH stimulation test, also known as the cosyntropin stimulation test or Synacthen test. This test measures how well your adrenal glands can respond when stimulated. You’ll typically spend a morning at a medical facility where healthcare staff will take an initial blood sample to measure your baseline cortisol level. Then they’ll give you an injection of synthetic ACTH (called cosyntropin or Synacthen), which is a laboratory-made version of the hormone that normally tells your adrenal glands to produce cortisol.[4][13]

After receiving the injection, blood samples are taken at specific time intervals—usually 30 and 60 minutes later—to see how your cortisol levels respond. In people with healthy adrenal glands, cortisol levels should rise significantly after the injection. If your cortisol level doesn’t increase adequately, this confirms that your adrenal glands aren’t working properly. The test is relatively quick and generally well-tolerated, though you may feel slightly flushed or experience mild nausea from the injection.[4][11]

Once adrenal insufficiency is confirmed, the next step is figuring out what type you have and what’s causing it. This is where measuring ACTH levels becomes crucial. A blood test to check your ACTH level helps distinguish between primary adrenal insufficiency (also called Addison’s disease) and secondary adrenal insufficiency. In primary adrenal insufficiency, where the adrenal glands themselves are damaged, ACTH levels are very high because the pituitary gland keeps sending signals to adrenal glands that can no longer respond. Think of it like someone repeatedly ringing a doorbell when nobody’s home—the pituitary keeps producing more ACTH trying to get a response.[1][13]

In secondary adrenal insufficiency, the problem lies with the pituitary gland not producing enough ACTH in the first place. Here, both ACTH and cortisol levels are low because the signal from the brain never reaches the adrenal glands adequately. This distinction matters because it affects treatment—people with primary adrenal insufficiency need replacement of both cortisol and another hormone called aldosterone, while those with secondary insufficiency typically need only cortisol replacement since aldosterone production remains normal.[1][10]

Doctors may also test for antibodies in your blood, particularly 21-hydroxylase antibodies. These antibodies are proteins that attack parts of the adrenal glands, and they’re present in more than 90 percent of people with autoimmune Addison’s disease. Finding these antibodies helps identify the cause as autoimmune disease, which is the most common reason for primary adrenal insufficiency in developed countries. Interestingly, these antibodies can sometimes be detected years before symptoms actually develop.[13]

Testing for electrolytes—the minerals in your blood—provides additional clues. People with primary adrenal insufficiency often have low sodium levels and high potassium levels because they aren’t producing enough aldosterone, the hormone that regulates these minerals. Your blood pressure may also be measured lying down and then standing up, as many people with adrenal insufficiency experience a significant drop in blood pressure when standing, causing dizziness or lightheadedness. This is called postural hypotension.[2][3]

Blood glucose (sugar) testing may reveal episodes of hypoglycemia, or low blood sugar, because cortisol normally helps maintain blood sugar levels. Without enough cortisol, blood sugar can drop, especially between meals or during illness. This is particularly important to identify in children with adrenal insufficiency, who are more vulnerable to dangerous drops in blood sugar.[5]

For people with primary adrenal insufficiency, doctors may recommend imaging tests to look at the adrenal glands and search for a cause. A CT scan (computed tomography scan) of the abdomen can check the size and appearance of the adrenal glands. Small, shrunken adrenal glands typically suggest autoimmune destruction, while enlarged glands might indicate infection, bleeding, or tumors. In some cases, tuberculosis or other infections can damage the adrenal glands, particularly in regions where these infections are more common.[12]

If secondary adrenal insufficiency is suspected, an MRI scan (magnetic resonance imaging) of the pituitary gland helps identify problems like pituitary tumors, damage from surgery or radiation, or other abnormalities that could explain why the pituitary isn’t producing enough ACTH. This imaging is painless and provides detailed pictures of the brain structures.[12]

In certain situations, doctors may perform additional specialized tests. The insulin-induced hypoglycemia test is sometimes used to diagnose secondary adrenal insufficiency when other tests are inconclusive. This test involves giving an insulin injection to lower your blood sugar, which creates stress that should trigger cortisol release. Blood samples are taken to measure cortisol levels in response to this stress. This test must be done in a carefully monitored medical setting because deliberately lowering blood sugar carries risks.[12]

Some people may also undergo testing to measure plasma renin activity, particularly those with primary adrenal insufficiency. Renin is produced by the kidneys in response to low blood pressure and low sodium, and measuring it helps doctors understand how well aldosterone replacement is working. If renin levels are very high, it may indicate that aldosterone dosing needs adjustment.[11]

Diagnostics for Clinical Trial Qualification

When researchers design clinical trials to study new treatments or better understand adrenal insufficiency, they use specific diagnostic criteria to determine who can participate. These criteria ensure that everyone enrolled truly has the condition and that results can be compared fairly across participants. Understanding these requirements can be helpful if you’re considering participating in research studies.[1]

Clinical trials for adrenal insufficiency typically require documented proof of diagnosis through the ACTH stimulation test. Participants must usually demonstrate that their cortisol levels fail to rise adequately after receiving synthetic ACTH. The specific threshold—meaning exactly how low the cortisol response must be—varies somewhat between studies but generally follows established medical guidelines. Some trials require that peak cortisol levels remain below a certain number (often 18 micrograms per deciliter) even after stimulation.[11]

For studies specifically examining primary adrenal insufficiency or Addison’s disease, researchers often require elevated ACTH levels in addition to the abnormal stimulation test results. This confirms that the adrenal glands themselves are the problem rather than the pituitary. Some trials may also require the presence of 21-hydroxylase antibodies to ensure participants have the autoimmune form of the disease, especially if the study is investigating autoimmune processes or prevention strategies.[13]

Trials may have additional requirements depending on what they’re studying. If researchers are investigating aldosterone replacement strategies, they’ll need confirmation of mineralocorticoid deficiency through measurements of plasma renin activity or aldosterone levels. Studies looking at quality of life or symptoms might require detailed questionnaires about fatigue, mood, or daily functioning in addition to hormone measurements.[11]

Most clinical trials exclude people who have certain other medical conditions or who are taking specific medications that could interfere with study results. For example, studies might exclude individuals with uncontrolled diabetes, severe heart disease, active infections, or certain types of cancer. Women who are pregnant or planning to become pregnant are typically excluded from trials testing new medications due to potential risks to the developing baby.[1]

Researchers may also require recent laboratory results—usually within the past few months—to ensure that hormone levels and general health status are current and stable. You might need to undergo repeat testing even if you’ve been diagnosed previously, as trial protocols often specify exactly which laboratory must perform the tests and what methods should be used to ensure consistency.[11]

If you’re interested in participating in a clinical trial, your endocrinologist can help determine whether you meet the eligibility criteria and can provide the necessary documentation of your diagnosis and test results. Many trials are listed on publicly available databases where you can search by condition and location to find studies currently recruiting participants.[1]

Prognosis and Survival Rate

Prognosis

The outlook for people diagnosed with adrenal insufficiency has improved dramatically with modern treatment. With appropriate hormone replacement therapy, most people can lead normal, active lives with minimal restrictions. The key to a good prognosis is proper diagnosis, consistent medication use, and learning how to adjust treatment during times of stress or illness.[1]

However, prognosis depends heavily on patient education and careful management. People with adrenal insufficiency face the risk of adrenal crisis, a life-threatening emergency that can occur during severe illness, injury, surgery, or times of extreme physical stress. Those who understand their condition, carry emergency medication, wear medical identification, and know when to increase their medication or seek emergency help generally do very well.[7][14]

Individuals with primary adrenal insufficiency need to remain vigilant for the development of other autoimmune conditions. Research shows that up to 50 percent of people with autoimmune Addison’s disease develop another autoimmune disorder during their lifetime. Common associated conditions include thyroid disease, Type 1 diabetes, celiac disease, and vitiligo. Regular monitoring allows early detection and treatment of these conditions if they arise.[13]

Quality of life can be affected even with treatment. Some people report persistent fatigue, reduced energy levels, difficulty concentrating, or mood changes despite taking their medications as prescribed. Finding the right medication dose and schedule is an ongoing process that requires communication with healthcare providers. Some individuals benefit from adjustments to their treatment regimen or from additional support for managing symptoms.[1]

Survival rate

Adrenal insufficiency is rare, affecting approximately 1 in 100,000 people in the United States for Addison’s disease specifically. The condition can affect people of all ages, though it’s most commonly diagnosed in people between 30 and 50 years old.[7][9]

Without treatment, adrenal insufficiency can be fatal, particularly if an adrenal crisis occurs. However, with proper hormone replacement and appropriate management during times of stress or illness, survival and life expectancy can approach that of the general population. The most significant risk to survival comes from unrecognized or inadequately treated adrenal crises, which underscores the critical importance of patient education, carrying emergency supplies, and wearing medical identification at all times.[6][14]

Historical data shows that before effective treatment became available, Addison’s disease was usually fatal within months to a few years of diagnosis. The introduction of synthetic cortisol replacement in the 1950s transformed this condition from a death sentence to a manageable chronic condition. Today, the greatest challenges involve ensuring consistent access to medication, preventing adrenal crises, and optimizing quality of life rather than simply survival.[13]

Ongoing Clinical Trials on Adrenal insufficiency

  • Study on Hydrocortisone for Stress in Patients with Polymyalgia Rheumatica or Giant Cell Arteritis and Adrenal Insufficiency

    Not recruiting

    1 1 1
    Investigated diseases:
    Investigated drugs:
    Denmark

References

https://www.niddk.nih.gov/health-information/endocrine-diseases/adrenal-insufficiency-addisons-disease/definition-facts

https://www.endocrine.org/patient-engagement/endocrine-library/adrenal-insufficiency

https://www.mayoclinic.org/diseases-conditions/addisons-disease/symptoms-causes/syc-20350293

https://www.pituitary.org.uk/information/adrenal-insufficiency/

https://www.chop.edu/conditions-diseases/adrenal-insufficiency-addison-s-disease

https://medlineplus.gov/addisondisease.html

https://my.clevelandclinic.org/health/diseases/15095-addisons-disease

https://www.niddk.nih.gov/health-information/endocrine-diseases/adrenal-insufficiency-addisons-disease/treatment

https://my.clevelandclinic.org/health/diseases/15095-addisons-disease

https://www.nadf.us/secondary-adrenal-insufficiency.html

https://www.endocrine.org/clinical-practice-guidelines/primary-adrenal-insufficiency

https://www.mayoclinic.org/diseases-conditions/addisons-disease/diagnosis-treatment/drc-20350296

https://www.aafp.org/pubs/afp/issues/2014/0401/p563.html

https://naemsp.org/adrenal-crisis-and-addisons-disease-what-ems-needs-to-kno/

https://www.nadf.us/a-day-in-the-life.html

https://draxe.com/health/adrenal-insufficiency/

https://www.addisonsdisease.org.uk/newly-diagnosed-sick-day-rules

https://www.pituitary.org.uk/information/adrenal-insufficiency/

https://www.endocrine.org/patient-engagement/endocrine-library/adrenal-insufficiency

https://pmc.ncbi.nlm.nih.gov/articles/PMC6297573/

https://www.doctronic.ai/conditions-diseases/living-well-with-adrenal-insufficiency-your-daily-management-guide-mYyazO/

https://medlineplus.gov/diagnostictests.html

https://www.questdiagnostics.com/

https://www.healthdirect.gov.au/diagnostic-tests

https://www.who.int/health-topics/diagnostics

https://www.yalemedicine.org/clinical-keywords/diagnostic-testsprocedures

https://www.nibib.nih.gov/science-education/science-topics/rapid-diagnostics

https://www.health.harvard.edu/diagnostic-tests-and-medical-procedures

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Adrenal insufficiency:

FAQ

How long does it take to get diagnosed with adrenal insufficiency?

The diagnostic process can vary considerably depending on your symptoms and circumstances. The ACTH stimulation test itself takes only a few hours at a medical facility. However, many people experience symptoms for months or even years before the correct diagnosis is made because the symptoms develop gradually and can be mistaken for other conditions like depression, chronic fatigue, or stress. Once your doctor suspects adrenal insufficiency and orders the appropriate tests, confirmation typically takes a few days to a couple of weeks to receive all results.[3][13]

Can adrenal insufficiency be diagnosed with a simple blood test?

Not exactly. While blood tests are essential for diagnosis, they need to be specific ones at specific times. A single random cortisol blood test usually isn’t enough because cortisol levels vary throughout the day. The ACTH stimulation test, which involves taking blood before and after an injection, is the gold standard for confirming the diagnosis. Additional blood tests measuring ACTH levels, electrolytes, and antibodies help determine the type and cause of adrenal insufficiency.[2][11]

Do I need to prepare for the ACTH stimulation test?

Your doctor will give you specific instructions, but generally the test is performed in the morning when cortisol levels are naturally higher. You may be asked to avoid certain medications temporarily, though this depends on your situation. The test typically requires you to be at a medical facility for a few hours. It’s a good idea to bring something to read or do while waiting between blood draws. Most people can eat normally beforehand unless told otherwise.[4][12]

Will I need repeated testing after being diagnosed?

Once diagnosed, you generally won’t need to repeat the ACTH stimulation test unless there’s a question about the original diagnosis. However, you will need regular blood tests to monitor your treatment. For primary adrenal insufficiency, doctors typically check electrolyte levels and plasma renin activity to ensure your aldosterone replacement is correct. Blood pressure measurements and assessments of your symptoms help determine if your cortisol replacement dose is appropriate. These monitoring tests are usually done every few months initially, then less frequently once treatment is stable.[11][12]

What if my test results are borderline or unclear?

Sometimes test results fall into a gray area where they’re not clearly normal or clearly abnormal. In these situations, your doctor might recommend repeat testing at a different time, additional specialized tests like the insulin-induced hypoglycemia test, or a period of careful monitoring with repeated measurements. The decision to start treatment may depend on how severe your symptoms are, even if test results aren’t definitive. If you’re taking medications that could affect the adrenal glands, your doctor might need to adjust or temporarily stop those medications before retesting.[12][19]

🎯 Key takeaways

  • • The ACTH stimulation test is the gold standard for diagnosing adrenal insufficiency and involves checking how your cortisol responds to synthetic hormone stimulation over a few hours.
  • • Measuring ACTH levels helps distinguish whether the problem lies in your adrenal glands themselves or in the pituitary gland that signals them.
  • • Many people live with symptoms for months or years before diagnosis because the signs develop so gradually they’re mistaken for stress, aging, or depression.
  • • Anyone taking steroid medications like prednisone for three weeks or longer should never stop suddenly without medical guidance, as this can cause dangerous adrenal insufficiency.
  • • The antibodies that attack the adrenal glands in autoimmune Addison’s disease can appear in blood tests years before symptoms start, offering a window for early detection in at-risk individuals.
  • • People with one autoimmune disease face higher risk of developing autoimmune adrenal insufficiency and should be alert to symptoms that might warrant testing.
  • • Darkened patches of skin, especially around scars, skin creases, and gums, combined with fatigue and salt cravings, are distinctive signs that should prompt evaluation.
  • • With proper diagnosis and treatment, most people with adrenal insufficiency can lead normal, active lives—the key is education, consistent medication use, and knowing when to adjust doses during illness or stress.

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