Adrenal function is checked with timed hormone blood, urine, or saliva tests, then response-based tests, and imaging only when results point to a cause.
Your adrenal glands sit above your kidneys. They make cortisol, aldosterone, and adrenal androgens. Those hormones shape energy, blood pressure, salt balance, and the way your body reacts during illness or stress. When levels drift, the signs can be fuzzy: fatigue that won’t lift, dizziness on standing, unexplained weight change, new stretch marks, stubborn high blood pressure, or spells of pounding heartbeat.
Testing follows a simple logic. Start with baseline labs taken at the right time of day. If the result is unclear, use a “dynamic” test that checks whether the gland can respond to a trigger. If the pattern looks real, then look for the source with focused scans.
Adrenal lab tests and what they answer
This table is a practical overview of the tests most often used when a clinician is checking adrenal output. Your symptoms and first results decide which ones belong on your list.
| Test | What it measures | What question it helps answer |
|---|---|---|
| Morning serum cortisol | Cortisol near the daily peak | Is cortisol low enough to raise concern, or high enough to prompt a cortisol-excess screen? |
| Plasma ACTH | Pituitary ACTH signal | If cortisol is low, is the body trying to push the adrenals (high ACTH) or not (low/normal ACTH)? |
| ACTH (cosyntropin) stimulation test | Cortisol rise after synthetic ACTH | Can the adrenal cortex respond and raise cortisol when asked? |
| Late-night salivary cortisol | Cortisol at bedtime | Is cortisol staying high late at night, a common sign of cortisol excess? |
| 24-hour urine free cortisol | Total free cortisol output in a day | Is cortisol output high across a full day, not just at one moment? |
| Overnight dexamethasone suppression test | Cortisol after a dexamethasone dose | Can the body turn cortisol down after a glucocorticoid signal? |
| Aldosterone and renin | Salt-and-water hormone system | Is aldosterone too high (common in primary aldosteronism) or too low (seen in some adrenal failure patterns)? |
| Electrolytes and glucose | Sodium, potassium, glucose | Do blood salts and sugar fit with the hormone pattern and symptom story? |
| DHEA-S | Adrenal androgen marker | Is the adrenal gland a likely source of androgen changes? |
| 17-hydroxyprogesterone | CAH screen marker | Is a congenital enzyme pattern affecting adrenal steroid production? |
| Plasma free metanephrines or urine metanephrines | Catecholamine breakdown products | Do episodic symptoms point toward a catecholamine-secreting adrenal tumor? |
What Tests Are Done to Check Adrenal Function? For common concerns
Clinicians choose tests by matching symptoms to a hormone system. Below are the most common routes, written in plain terms. If you’ve been searching “what tests are done to check adrenal function?” this section is the one that usually clicks.
Suspected low cortisol or adrenal insufficiency
A typical start is a morning cortisol paired with ACTH. Cortisol changes through the day, so timing matters. A random afternoon cortisol can look low even in a healthy person.
Clinicians often pair hormone tests with basic labs like sodium, potassium, and glucose. With primary adrenal failure, low sodium and high potassium may appear, yet early cases can still look normal. Low morning glucose can also fit, more often in adults and children. If a first result lands in a gray zone, repeating the draw at the right time, on a steadier day, can beat chasing one odd number. Tell the team about any steroid exposure: pills, inhalers, nasal sprays, skin creams, joint injections, or IV doses. Steroids can blunt ACTH and cortisol for weeks, and they can change which test is safest. Also mention pregnancy, oral estrogen, and biotin supplements, since they can shift some lab methods. Bring timing details too: when you woke up, when you ate, and whether you were sick or short on sleep.
If cortisol is low, an ACTH stimulation test often follows. You get a small dose of lab-made ACTH, then your blood is checked again after a set interval. A normal rise makes primary adrenal failure less likely. A poor rise raises concern and shifts the workup toward sorting primary versus central causes.
For a clear description of the ACTH stimulation test steps and how it fits into diagnosis, see the U.S. National Institute of Diabetes and Digestive and Kidney Diseases page on adrenal insufficiency diagnosis.
Suspected cortisol excess
Cortisol excess can mimic many common problems, so screening usually uses more than one test type. Three widely used screens are late-night salivary cortisol, 24-hour urine free cortisol, and the overnight dexamethasone suppression test.
Late-night saliva testing looks for cortisol that stays high at bedtime. Urine testing looks for total output across a day. Dexamethasone testing checks whether cortisol turns down after a signal that should slow production. When two different screens line up, clinicians move to confirm tests and source-finding.
High blood pressure with low potassium or hard-to-control readings
This pattern can raise suspicion for excess aldosterone. Renin and aldosterone are checked together, often with specific posture, diet, and timing instructions. If screening suggests primary aldosteronism, confirm tests may follow before scans or vein sampling are chosen.
New androgen changes
DHEA-S can help show whether the adrenal gland is contributing to androgen shifts. When congenital adrenal hyperplasia is a possibility, 17-hydroxyprogesterone is a common first screen, sometimes repeated with ACTH stimulation if the first value lands in a gray zone.
Spells of pounding heartbeat, sweating, headache, or tremor
These episodic symptoms can fit a catecholamine release pattern. Plasma free metanephrines or urine metanephrines are used because they stay measurable longer than adrenaline itself. Pre-test conditions matter. Some clinics ask you to rest quietly before a blood draw. Some medicines and stimulants can interfere, so the ordering team may review them first.
How to get cleaner numbers from adrenal tests
Adrenal testing is sensitive to timing, sleep, and medicines. You’re not trying to “beat” the test. You’re trying to avoid a false signal that sends you down the wrong track.
Match testing to your sleep schedule
If you work nights or sleep late, tell the clinician and the lab. A “morning cortisol” is meant to match your wake period. Late-night salivary cortisol also needs to match your usual bedtime, not midnight on a clock.
Bring a full medicine list
Steroid medicines can change results even when they’re not pills. That includes inhalers, nasal sprays, skin creams, joint injections, and recent IV steroids. Oral estrogen can change total cortisol readings. Some seizure medicines and antifungals can shift steroid metabolism. Write down what you take and when you last used it.
Avoid short-term stressors when possible
Acute illness, pain flares, and heavy training weeks can raise cortisol. If you’re running a fever or dealing with a big injury, ask if it makes sense to delay a cortisol-excess screen until you’re back near baseline.
What the dynamic tests are trying to prove
Dynamic tests check response, not just a single snapshot. Here’s how the most common ones differ in what they’re designed to show.
| Dynamic test | Response being checked | Typical setup |
|---|---|---|
| ACTH stimulation | Cortisol should rise after synthetic ACTH | Baseline blood draw, injection, repeat draw at set times |
| Overnight dexamethasone suppression | Cortisol should fall after dexamethasone | Dose at night, blood draw in the morning |
| Late-night salivary cortisol | Cortisol should be low near bedtime | Home sample, collected at a prescribed time window |
| 24-hour urine free cortisol | Total cortisol output should stay in range | Collect all urine for 24 hours, then return container |
| Insulin tolerance test | Cortisol should rise during controlled low glucose | Monitored setting with frequent glucose checks |
| Confirm tests for aldosterone excess | Aldosterone should drop under salt or fluid loading | Clinic protocol varies; med plan often adjusted first |
| Metanephrine sampling conditions | Metanephrines should stay in range at rest | Rest period before draw; review interfering substances |
When imaging enters the picture
Scans are usually not the first step. Imaging is used after labs show a pattern that needs a source. A CT or MRI can check adrenal size, nodules, or masses. If ACTH patterns point away from the adrenal gland, a pituitary MRI may be used. In aldosterone workups, adrenal vein sampling can be used in select cases to find which gland is overproducing, since incidental adrenal nodules are common and can distract from the real source.
Safety notes and urgent symptom patterns
Some situations call for urgent care, not routine testing. Severe weakness with vomiting, fainting, confusion, or severe abdominal pain can fit an adrenal crisis pattern, especially after long-term steroid use that was stopped suddenly or in someone with known adrenal insufficiency. Sudden extreme blood pressure spikes with chest pain, shortness of breath, or neurologic symptoms also calls for emergency evaluation.
Questions that keep the process clear
These questions can help you track what each test is meant to do and what decision it drives:
- Which hormone system are we checking: cortisol, aldosterone, adrenal androgens, or catecholamines?
- What exact time should I collect the sample based on my sleep schedule?
- Which medicines can skew this test, and what’s the safe plan around them?
- If this screen is abnormal, what confirm test comes next?
- What result would change treatment, and what result would end the workup?
What most readers can take away
Adrenal testing isn’t random. It’s a stepwise sequence: baseline labs, a response test when needed, then source-finding scans. When you know which hormone is the target, the test list makes sense. If you still find yourself asking “what tests are done to check adrenal function?”, ask the ordering clinician to name the target hormone and the next action the result will trigger. That keeps your time, blood draws, and follow-ups focused.
Mo Maruf
I created WellFizz to bridge the gap between vague wellness advice and actionable solutions. My mission is simple: to decode the research and give you practical tools you can actually use.
Beyond the data, I am a passionate traveler. I believe that stepping away from the screen to explore new environments is essential for mental clarity and physical vitality.