Cortisol Test: What It Measures, When It Helps, and What It Cannot Tell You

주요 테이크 아웃

• Timing drives meaning: cortisol follows a daily rhythm, so the same number can be normal at 8 a.m. and abnormal at midnight.
• One value rarely settles the question: dynamic tests such as the short Synacthen (ACTH stimulation) test or overnight dexamethasone suppression test are usually needed.
• A normal result is not an exclusion: it describes that sample, at that moment, under those conditions.
• Common medicines and conditions distort results in predictable directions, oestrogen-containing pills, steroids in any form, pregnancy, critical illness, shift work.
• "Adrenal fatigue" is not a recognised medical diagnosis; cortisol testing does not diagnose it.

한눈에

라고도

• Serum cortisol, plasma cortisol
• Morning cortisol, 8 a.m. cortisol
• Late-night salivary cortisol (LNSC)
• 24-hour urinary free cortisol (UFC)
• Commonly asked for in India as the "cortisol hormone test", "stress hormone test" or "adrenal test"
• Related but different: ACTH test, Synacthen test, dexamethasone suppression test

What the cortisol test is

Cortisol is produced by the adrenal glands under the control of ACTH from the pituitary gland. Cortisol helps regulate blood glucose, blood pressure, the immune response and the body's handling of physical stress. Cortisol secretion is pulsatile and follows a circadian rhythm, highest in the early morning, lowest around midnight in someone with a conventional sleep pattern.

Because of that rhythm, the cortisol test is interpreted together with the exact time the sample was taken. The three sample types answer different questions:

• Serum cortisol: a snapshot. Most useful early in the morning when suspecting adrenal insufficiency, or as part of a dynamic test.
• Late-night salivary cortisol: tests whether the normal night-time fall in cortisol is preserved. Used when Cushing's syndrome is suspected.
• 24-hour urinary free cortisol: an integrated measure of cortisol output over a day. Also used in suspected Cushing's syndrome.

Why the cortisol test is done

• 부신 기능 부전 의심 (including Addison's disease): unexplained fatigue with weight loss, low blood pressure or postural dizziness, low sodium, salt craving, darkening of skin creases, unexplained low blood glucose.
• Suspected Cushing's syndrome: easy bruising, purple stretch marks, proximal muscle weakness, new or difficult-to-control diabetes and hypertension together, fat redistribution, thinning skin.
• Suspected secondary adrenal insufficiency after pituitary disease, pituitary surgery, head injury, or after prolonged glucocorticoid use is reduced or stopped.
• Adrenal incidentaloma: an adrenal mass found on a scan done for another reason often needs hormonal assessment.
• 모니터링 treatment for known adrenal or pituitary disease, as directed by an endocrinologist.
• Acute illness: a random cortisol is sometimes checked in a patient who is collapsing or in shock with a suspected adrenal crisis, here treatment is started before results return.

누가 이 검사를 받아야 할까요?

The cortisol test is a targeted test, not a general screening or "wellness" test. It is appropriate when:

• A doctor has found a clinical pattern that fits cortisol excess or deficiency.
• You have had pituitary or adrenal surgery, radiotherapy or a known tumour.
• You have taken oral, injectable, inhaled or potent topical steroids for a prolonged period and your doctor is assessing adrenal recovery.
• An adrenal mass has been found incidentally.
• You have unexplained electrolyte disturbance, recurrent hypoglycaemia, or resistant hypertension with hypokalaemia.

Who generally does not need it: people who feel tired, stressed or burnt out without any of the above features. In that group a cortisol test rarely changes management and abnormal-looking results more often reflect timing, medicines or illness than adrenal disease. Speak to a doctor about what is actually driving the symptoms, thyroid disease, anaemia, sleep disorders, depression and diabetes are far more common explanations.

What the cortisol test cannot detect or exclude

• It cannot diagnose or exclude "adrenal fatigue" or "burnout". These are not recognised endocrine diagnoses and no cortisol pattern defines them.
• A single normal cortisol does not exclude Cushing's syndrome. Cortisol excess can be intermittent (cyclical Cushing's), and mild cases may give normal screening results. Repeat or alternative testing may be needed.
• A single normal cortisol does not exclude adrenal insufficiency, particularly partial or secondary insufficiency. A stimulation test is usually required.
• It does not localise the problem. A high cortisol does not tell you whether the source is the pituitary, an adrenal tumour, an ACTH-producing tumour elsewhere, or exogenous steroids. That requires ACTH measurement, suppression testing and imaging.
• It does not measure "how stressed you are" in any clinically useful way, and it cannot quantify psychological stress.
• It does not measure tissue steroid effect. Someone on steroid medication can have a low measured cortisol while being heavily steroid-exposed, because most assays do not detect synthetic steroids such as prednisolone or dexamethasone.
• It does not assess the other adrenal hormones. Aldosterone, renin, DHEAS and catecholamines are separate tests.
• A negative or normal result is not the same as a condition being ruled out. If symptoms persist despite a normal cortisol result, return to your doctor rather than assuming the question is closed.

관련은 있지만 서로 다른 시험들

None of these tests is universally "better". Which one comes first depends on the clinical question: suspected cortisol deficiency usually starts with an early-morning serum cortisol; suspected cortisol excess usually starts with late-night salivary cortisol, 24-hour urinary free cortisol or an overnight dexamethasone suppression test, chosen by the treating clinician.

준비 방법

Preparation is set by the laboratory and by the specific protocol your doctor has ordered. Instructions differ between units and assays, and your own unit's written instructions take precedence over anything on this page.

• Tell your doctor about every steroid exposure: tablets, injections into joints, inhalers, nasal sprays, eye drops, potent skin creams, and unlabelled ayurvedic, homeopathic, herbal or gym/bodybuilding preparations. Several such products have been found to contain undeclared steroids, which suppress cortisol.
• List all medicines and supplements, including oestrogen-containing contraceptives, hormone therapy, antiepileptics, rifampicin and antifungals.
• 처방받은 약을 중단하거나 변경하지 마십시오.: including steroids, to prepare for this test. Ask the prescriber; stopping steroids abruptly can be dangerous.
• Sleep and shift work: mention night shifts or recently crossed time zones, as they shift the cortisol rhythm.
• 금식: not routinely needed for cortisol alone in many laboratories, but is sometimes required when other tests are drawn at the same time. Confirm with your collection centre.
• Salivary samples: typically no food, drink, smoking, tobacco/paan, or tooth brushing for a period before collection, and no bleeding gums at the time. Follow the exact window on your kit.
• 24-hour urine: discard the first morning sample, then collect every drop for 24 hours including the next morning's first sample, and store as the laboratory instructs.

임신 중이거나 수유 중인 경우

Cortisol and cortisol-binding globulin rise physiologically in pregnancy, so standard reference intervals and standard screening tests do not apply straightforwardly. Testing in pregnancy should be arranged and interpreted with endocrine input.

당뇨병이 있고 혈당 강하 치료를 받고 있다면

If you are asked to fast, or to attend for a dynamic test, ask the prescriber in advance how to handle insulin or sulfonylureas that morning, and carry glucose with you. Do not fast for long periods without that advice.

만약 만성 신장 질환이 있다면

24-hour urinary free cortisol becomes unreliable as kidney function falls, and results may be misleadingly low. Discuss alternative tests with your doctor.

심부전이 있거나 수분 섭취가 제한된 경우

Do not increase fluid intake for a urine collection. Collect whatever volume you pass normally and continue your prescribed restriction.

어린이

Paediatric cortisol testing, dosing for stimulation tests and interpretation differ from adults and should be supervised by a paediatrician or paediatric endocrinologist. Salivary collection is often preferred to reduce needle stress, using age-appropriate devices.

고령자

Multiple medicines, poor sleep, intercurrent illness and difficulty completing a full 24-hour collection all make interpretation harder. Simpler, better-timed testing is often more useful.

What happens during the cortisol test

• 혈액 샘플: a tourniquet is applied, blood is drawn from a vein in the arm and the collection time is recorded. The draw itself takes a few minutes.
• Late-night salivary sample: you collect at home at the specified time, usually around 11 p.m. to midnight, by chewing a swab or drooling into a tube, then store and return it as instructed. Each sample takes a few minutes.
• 24-hour urine: collection runs across a full day and night in a labelled container.
• Short Synacthen test: a baseline sample, an injection of synthetic ACTH, then one or two further samples at set intervals. Expect to stay in the day-care area roughly 30-60 minutes, sometimes longer depending on protocol.
• Overnight dexamethasone suppression test: a tablet at a specified late hour at home, followed by a blood sample the next morning.

Results vary depending on individual clinical circumstances, and the reporting time depends on whether the assay is run in-house or referred to a central laboratory. Ask your collection centre when to expect the report.

Understanding your cortisol report

Read the cortisol result together with three things printed on or attached to the report: the sample type, the exact time of collection, and the laboratory's own reference interval. Cortisol assays differ between platforms, so reference intervals are laboratory-specific and results from two laboratories are not directly comparable. Do not compare your number with a range found online or in an older report from a different laboratory.

대략적으로 말하자면:

• A clearly high result raises the possibility of cortisol excess, from steroid medication, a pituitary adenoma (Cushing's disease), an adrenal tumour, or ectopic ACTH production. It can also reflect acute illness, pain, pregnancy, oestrogen therapy or severe stress at the time of sampling.
• A clearly low result, especially early in the morning with matching symptoms, raises the possibility of adrenal insufficiency, primary (adrenal) or secondary (pituitary/hypothalamic), including suppression from steroid treatment.
• An intermediate result is common and frequently uninformative on its own. This is usually where dynamic testing is added.

The cortisol test does not by itself make a diagnosis. Interpretation belongs to the doctor who requested it, in the context of your symptoms, examination and medicines.

When cortisol results can be misleading

Results that can be falsely raised

• Oestrogen-containing contraceptives, hormone therapy and pregnancy: raise cortisol-binding globulin, so total serum cortisol rises even when free, active cortisol is normal.
• Acute illness, sepsis, surgery, trauma, severe pain, uncontrolled epilepsy: genuine stress-driven rises that do not indicate Cushing's syndrome.
• Depression, chronic alcohol use, poorly controlled diabetes, obstructive sleep apnoea: can produce mild cortisol excess and abnormal suppression tests without Cushing's syndrome.
• Night-shift work or recent long-haul travel: a "late-night" sample may be taken at the person's physiological morning.
• Salivary sample contamination: steroid creams, inhaler residue, tobacco/paan, food or blood from gums in the mouth can distort salivary readings.
• Drugs that speed dexamethasone clearance (rifampicin, phenytoin, carbamazepine, phenobarbitone) can make a suppression test look falsely non-suppressed.

Results that can be falsely lowered

• Any glucocorticoid exposure, including inhaled, nasal, intra-articular, topical or hidden steroids in unlabelled supplements and some traditional remedies.
• Sampling in the afternoon or evening, when cortisol is physiologically low, a "low cortisol" at 6 p.m. usually means nothing.
• Low binding proteins: nephrotic syndrome, severe liver disease, protein-losing states and critical illness lower total cortisol while free cortisol may be adequate.
• Incomplete 24-hour urine collection: the single commonest reason for a misleadingly low urinary free cortisol.
• 만성 신장 질환 which reduces urinary cortisol excretion.
• Drugs that block steroid synthesis or interfere with specific assays, and biotin supplements, which can interfere with some immunoassays.

If a result does not fit the clinical picture, repeating the test under controlled conditions is often more informative than acting on the first number.

위험 및 안전

혈액 샘플링

Risks are small and mostly local: brief pain, bruising, light-headedness, and uncommonly a small haematoma or, rarely, infection at the puncture site. Tell the phlebotomist if you take blood thinners or have fainted during blood tests before.

Salivary and urine collection

These involve no needle and no physical risk. The main issue is sampling error rather than harm.

Short Synacthen (ACTH stimulation) test

Generally well tolerated. Flushing, a metallic taste or transient nausea can occur. Allergic reactions to synthetic ACTH are uncommon but have been reported, so the test is performed where staff and resuscitation facilities are available.

덱사메타손 억제 테스트

A single small steroid dose is usually uneventful. Transient insomnia, mood change or a rise in blood glucose can occur, which matters more if you have diabetes. Tell the requesting doctor if you have diabetes, active infection or a psychiatric illness before the test.

인슐린 내성 검사

Occasionally used in specialist centres to assess the HPA axis. This test deliberately induces hypoglycaemia, carries real risk, and is only performed with medical supervision and clear exclusions such as ischaemic heart disease or seizures.

특별한 상황

임신

Cortisol, cortisol-binding globulin and urinary free cortisol all rise as pregnancy progresses. Dexamethasone suppression testing performs poorly in pregnancy. Diagnosis in pregnancy relies on specialist interpretation, and imaging choices are also adjusted.

어린이

Growth failure, delayed puberty or unexplained weight change patterns are important clues in children. Reference intervals, stimulation-test doses and sample volumes are age-specific.

고령자

Symptoms of cortisol excess or deficiency overlap heavily with other age-related conditions and with polypharmacy. Careful drug review is part of interpretation.

People on long-term steroid therapy

Long-term steroids for asthma, arthritis, skin disease, nephrotic syndrome or transplant suppress the HPA axis. A low cortisol in this setting usually reflects the medicine, not new adrenal disease. Steroid reduction must be planned by the prescriber, and you may need a sick-day dose plan.

심각한 병

Cortisol interpretation in intensive care is a specialist judgement; usual thresholds and binding-protein assumptions do not hold.

The cortisol test in the Indian context

• Undisclosed steroid exposure is a real and frequent confounder. Over-the-counter steroid creams for skin conditions, steroid-containing joint injections, unregulated gym supplements and some unlabelled AYUSH or "pain relief" preparations can suppress cortisol or cause iatrogenic Cushing's syndrome. Bring every product you use, including packaging, to the consultation.
• Marketing claims: Indian law (the Drugs and Magic Remedies (Objectionable Advertisements) Act, 1954) restricts advertising that promises cures for such conditions. Be sceptical of "adrenal reset" or "cortisol detox" packages sold directly to consumers.
• Tuberculosis remains a cause of primary adrenal insufficiency in India, historically an important one, and adrenal calcification may be seen on imaging. Anti-tubercular therapy also matters for testing: rifampicin accelerates steroid metabolism and can both interfere with dexamethasone testing and increase steroid replacement requirements.
• 낮은 BMI에서도 대사 질환 발생 가능성 증가: South Asians develop diabetes and hypertension at lower body mass index, so the combination of early diabetes, hypertension and central fat distribution is common and usually not Cushing's syndrome. Cortisol testing is warranted when specific discriminatory features are present, such as easy bruising, proximal muscle weakness or wide purple striae.
• 분석 변동성: laboratories across India use different analysers and methods. Follow-up testing at the same laboratory makes comparison more meaningful.
• 데이터 보호 : personal health information collected for testing is subject to India's Digital Personal Data Protection Act, 2023. Ask how your reports and identity data are stored and shared.

인도의 비용 및 보험

Prices differ widely between government facilities, standalone laboratories and hospital-based endocrine units, and between cities. Rather than quoting a figure, ask for a written estimate before booking. The factors that move the cost are:

• 샘플 유형: a single serum cortisol is the least expensive option; salivary and 24-hour urinary cortisol usually cost more because of kits, handling and specialised assays.
• Number of samples: dynamic tests need multiple draws, so the cost multiplies.
• Drug cost of the stimulating or suppressing agent (synthetic ACTH, dexamethasone) and day-care or observation charges.
• 분석 방법 : mass spectrometry-based cortisol testing typically costs more than routine immunoassay and may be sent to a reference laboratory.
• 추가 테스트: ACTH, electrolytes, DHEAS, plasma renin/aldosterone, thyroid tests and imaging add substantially.
• Consultation and follow-up: endocrinology review, repeat testing and imaging are frequently part of the pathway.

Insurance behaviour also varies: outpatient diagnostic tests are often not covered unless linked to an admission or to a policy with a defined OPD benefit. Check with your insurer or the hospital's insurance desk before the test, and keep the prescription that states the clinical indication.

신화와 사실

자주하는 질문

What does a cortisol test actually check?

The cortisol test measures the amount of the hormone cortisol in a blood, saliva or urine sample. Doctors use the cortisol test to assess whether the adrenal glands are producing too much or too little cortisol, and whether the pituitary-adrenal control system is working as expected.

코르티솔 검사를 받으려면 금식을 해야 하나요?

Fasting is not routinely required for a cortisol measurement in many laboratories, but requirements differ by unit and by which other tests are booked with it. Confirm with your collection centre. If you take insulin or sulfonylureas and are asked to fast, ask the prescriber first.

Why must the blood sample be taken in the morning?

Cortisol follows a daily rhythm, peaking in the early morning. A morning sample is the most informative window when adrenal insufficiency is suspected, because a genuinely low morning value is meaningful, whereas a low evening value is usually physiological and uninformative.

전체 과정이 얼마나 걸립니까?

A blood draw takes a few minutes. A salivary sample takes two to five minutes at home. A 24-hour urine collection runs for a full day. A short Synacthen test usually means about 30 to 60 minutes in the day-care area, sometimes longer depending on the local protocol.

How is a saliva cortisol test different from a blood test?

Late-night salivary cortisol asks whether the normal night-time fall in cortisol has been lost, so it screens for cortisol excess. A morning blood cortisol asks whether baseline production is adequate. The salivary test cannot be used to diagnose low cortisol.

Can medicines change my cortisol result?

Yes, and in both directions. Oestrogen-containing pills and pregnancy raise total cortisol; steroids in any form, including creams, inhalers and hidden steroids in some supplements, lower it. Rifampicin and some antiepileptics distort dexamethasone testing. List everything you take.

My cortisol was slightly abnormal but I feel well. What next?

Mildly abnormal cortisol values are common and often reflect timing, medicines, sleep pattern or intercurrent illness. The usual step is review by the requesting doctor, sometimes with a repeat or a dynamic test under controlled conditions, rather than immediate treatment.

Is the cortisol test used to diagnose thyroid problems or PCOS?

No. Thyroid disease is assessed with thyroid function tests, and polycystic ovary syndrome with clinical criteria, androgen levels and ultrasound. Cortisol testing is sometimes added when features suggest Cushing's syndrome, which can mimic PCOS.

Can children have a cortisol test?

Yes. Paediatric cortisol testing is used for suspected adrenal insufficiency, congenital adrenal hyperplasia follow-up and steroid-related suppression. Doses for stimulation tests, sample volumes and reference intervals are age-specific and should be supervised by a paediatrician or paediatric endocrinologist.

지우면 좋을거같음 . SM

• Endocrine Society clinical practice guideline on the diagnosis of Cushing's syndrome
• Endocrine Society clinical practice guideline on the diagnosis and treatment of primary adrenal insufficiency
• European Society of Endocrinology and ENSAT guidance on the management of adrenal incidentalomas
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) patient information on Cushing's syndrome and adrenal insufficiency
• Drugs and Magic Remedies (Objectionable Advertisements) Act, 1954, Government of India
• 인도 정부의 2023년 디지털 개인정보 보호법