Platform
Company
Endocrine & Reproductive
Review status
Currently under review
Pending specialist review and validation.
Cortisol AM measures the level of cortisol in your blood collected in the early morning, when this hormone is typically at its daily peak. Cortisol is made by your adrenal glands and helps regulate energy, blood pressure, immune activity, and your body’s response to stress.
This test helps your clinician check how well your adrenal glands and the brain’s signaling system that controls them are working. Timing matters because cortisol follows a daily rhythm, with higher levels in the morning and lower levels later in the day.
This test helps evaluate conditions of low cortisol, such as adrenal insufficiency, and high cortisol, such as cortisol excess states. Your clinician may order it if you have symptoms like fatigue, weakness, dizziness, unintended weight changes, or changes in blood pressure, or if you take medicines that affect steroid hormones.
Morning cortisol also helps guide next steps, such as stimulation or suppression testing, and can be used with ACTH levels or tests collected at different times of day. It can support diagnosis and monitoring plans when interpreted alongside your history, medications, and physical exam.
Your result will be compared to the laboratory’s expected range for your age. A value below the expected range may suggest reduced adrenal function, but one measurement alone is not enough to diagnose a disorder. Illness, sleep disruption, or recent steroid use can lower levels. If results and symptoms point to adrenal insufficiency, your clinician may suggest an ACTH stimulation test or related evaluations.
A value above the expected range can be seen with physical or emotional stress, pregnancy, depression, or certain medicines. If levels are persistently high with compatible symptoms, your clinician may recommend tests such as late-night salivary cortisol, a dexamethasone suppression test, or a 24‑hour urine cortisol. Ask how to time any repeat samples so results are comparable.
Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.
Cortisol follows a daily rhythm, so collection in the early morning is important. Shift work, jet lag, or inconsistent sleep schedules can alter this rhythm and affect the result.
Pills, injections, inhaled or topical steroids (for example hydrocortisone, prednisone, dexamethasone) can raise or suppress measured cortisol or interfere with assays. Always tell your clinician about recent or current steroid use.
Pregnancy and estrogen therapy, including some birth control pills, increase cortisol-binding globulin, which can raise total cortisol while free cortisol may be unchanged. Your clinician will interpret results in this context.
Recent infection, surgery, trauma, fever, or significant psychological stress can transiently increase cortisol. Testing during recovery may give a clearer picture of your usual hormone status.
Drugs such as anticonvulsants, opioids, rifampin, and some antifungals can change cortisol metabolism or binding and shift results. Provide a complete medication and supplement list.
Fasting is usually not required, but consistent timing and proper collection are important. Delays in processing or significant hemolysis can affect some immunoassays and should be minimized.
References