High Cortisol Test Results: What Do They Mean and What Comes Next?

High cortisol test results mean the level of cortisol, a hormone made by the adrenal glands, was above the laboratory's reference range at the time of the test. This can happen with stress, illness, disrupted sleep, pregnancy, some medicines or oestrogen, as well as with Cushing's syndrome. A cortisol test alone cannot diagnose the cause, so abnormal results usually lead to further testing.

This guide is for adults who have a high cortisol result and want to prepare for the conversation with their clinician. It explains what can affect the result and how screening tests differ. It cannot interpret your own numbers, choose tests or advise on medicines.

Healthdirect notes that untreated Cushing's syndrome can make people very unwell. If you feel severely or suddenly unwell, use local urgent or emergency services rather than waiting for a routine follow-up.

• See a doctor promptly if you notice several changes developing together, such as a rounder or redder face, weight gain around the trunk, fat at the base of the neck, easy bruising, wide purple stretch marks or weakness in the upper arms and thighs.
• Mention it soon if you take steroid medicines and notice these changes. The NHS highlights steroid users in particular.
• Do not stop steroid medicine suddenly because of a cortisol result. Healthdirect warns this can make you very unwell. Any change should be agreed with the prescriber.

Cortisol follows a daily rhythm. Cleveland Clinic explains that levels peak in the morning around waking and are lowest in the evening. A morning blood cortisol is therefore expected to be higher than an afternoon one, and MedlinePlus notes that blood tests are sometimes taken twice in one day for this reason.

This is why the time printed on your sample matters. A morning value should be compared with what is expected for the morning. Ask your clinician what reference range applies to your sample time, since laboratories differ.

Write down when the sample was taken, whether you had slept normally the night before, and anything unusual that day, such as a stressful event, an illness or a long journey. These details are easy to forget later and can help the clinician decide whether a repeat test is worthwhile.

Yes. Cortisol is central to the body's stress response. MedlinePlus lists stress and exercise among the things that can raise cortisol, along with pregnancy and hot or cold temperatures. Cleveland Clinic notes that chronic sleep problems such as insomnia or night-shift work can raise cortisol too.

Physical stress also counts. The Endocrine Society guideline lists hospitalisation, surgery and pain as situations where cortisol can be raised without Cushing's syndrome. It also describes depression and other psychiatric conditions, poorly controlled diabetes and heavy alcohol use as possible causes of mild hypercortisolism that can produce test results suggesting Cushing's. MedlinePlus and NIDDK call this pseudo-Cushing's: cortisol rises and falls without the long-term effects of Cushing's syndrome.

It can. Cortisol in the blood travels partly attached to a carrier protein. The Endocrine Society guideline explains that oestrogens increase this cortisol-binding globulin, so total blood cortisol reads higher, while urine cortisol is not affected in the same way. MedlinePlus also lists birth control pills among medicines that can affect results.

This matters most for blood-based tests, including the overnight dexamethasone suppression test. The guideline reported false-positive results in about half of women taking the oral contraceptive pill. It discusses pausing oestrogen-containing medicines before testing where that is possible, but that is a decision for the clinician and you. Do not stop contraception or hormone therapy on your own.

Screening uses tests designed to show whether cortisol stays high when it should not. NIDDK says doctors usually use two tests, because no single test is perfect, and the Endocrine Society guideline describes the choice as depending on the person's circumstances. Common options are:

• 24-hour urine free cortisol: all urine is collected for a full day and the lab measures the cortisol in it. The guideline recommends at least two collections.
• Late-night salivary cortisol: saliva is collected in the late evening, often at home. Cortisol normally falls at night but stays raised in Cushing's syndrome. The guideline notes this test may not suit shift workers, people with variable bedtimes or recent long-distance travellers.
• Overnight dexamethasone suppression test: a steroid tablet is taken at night and blood is taken the next morning. Normally cortisol falls; cortisol that does not fall suggests Cushing's syndrome. Oestrogen and some other medicines can affect this test.
• Your team gives exact instructions for timing and preparation. Follow those rather than general information online.

Sometimes cortisol is tested because a scan found an adrenal nodule by chance. That assessment has its own approach. Our guide to incidental adrenal nodules explains why hormone testing is part of it and what to ask about the scan report.

Bring the report, the time each sample was taken, and a full list of medicines, including steroids in any form, contraceptives and hormone therapy.

• What kind of cortisol test was this, and what time was the sample taken?
• Could stress, recent illness, sleep, shift work, pregnancy or my medicines explain the result?
• Does my contraceptive or hormone therapy affect this test, and should anything change before a repeat?
• Which screening test, if any, do you recommend next, and why that one?
• How many results will be needed before you can draw a conclusion?
• Should I be referred to an endocrinologist, and who will contact me with results?

On SameCase, patients and verified doctors share de-identified cases. Reading cases where a high cortisol result came with similar circumstances, such as shift work, the pill or a recent illness, can show you which details clinicians asked about and help you prepare your own questions.

Other people's cases cannot tell you whether you have Cushing's syndrome or what your next test should be. Use them to prepare, and leave the interpretation to your care team.