Cortisol blood test

Overview

A cortisol blood test measures the level of cortisol, a hormone often called the 'stress hormone,' in your blood. Cortisol helps your body respond to stress, control blood sugar, reduce inflammation, and manage many other functions. This test helps doctors check whether your adrenal glands and pituitary gland are working properly.

The cortisol blood test is a common test ordered when a doctor suspects a problem with the adrenal glands or pituitary gland. Not everyone needs this test.

Anyone can have a cortisol blood test if their doctor recommends it. It is often done in people with symptoms that suggest too much or too little cortisol.

Symptoms

Common symptoms

• Unexplained weight gain, especially around the midsection
• High blood pressure
• Fatigue and weakness
• Mood changes, such as anxiety or depression
• Excessive thirst and urination
• Bruising easily

Symptoms in children

• Slow growth or delayed puberty
• Weight gain, especially in the face
• Excessive tiredness
• Frequent infections

Symptoms in older adults

• Fatigue and weakness
• High blood pressure that is hard to control
• Loss of bone density (osteoporosis)
• Muscle loss

Causes

Main causes

• Cushing's syndrome (too much cortisol) – often from a tumor in the pituitary or adrenal glands, or from taking high doses of steroid medications
• Addison's disease (too little cortisol) – usually due to an autoimmune attack on the adrenal glands
• Pituitary gland problems affecting ACTH (the hormone that tells the adrenal glands to make cortisol)
• Severe stress or illness

Risk factors

• Long-term use of steroid medications (e.g., prednisone, hydrocortisone) for conditions like asthma or arthritis
• Pituitary or adrenal tumors (benign or malignant)
• Autoimmune diseases that can affect the adrenal glands
• Family history of adrenal or pituitary disorders

When to see a doctor

See a doctor urgently if:

• Symptoms of adrenal crisis: severe vomiting, severe pain, confusion, fainting, or very low blood pressure

Book a routine appointment if:

• Ongoing unexplained weight gain, high blood pressure, fatigue, or mood changes
• Persistent thirst and urination
• Signs of low cortisol: chronic fatigue, weight loss, darkening of the skin, dizziness when standing

Diagnosis

A cortisol blood test is ordered by a doctor when symptoms suggest a hormone imbalance. The test measures the amount of cortisol in your blood at the time of the draw. Because cortisol levels change during the day, the test is often done in the morning.

Tests that may be done

• Cortisol blood test (morning or random)
• ACTH stimulation test – to check how well your adrenal glands respond to ACTH
• 24-hour urine cortisol test – to measure cortisol production over a full day
• Dexamethasone suppression test – to see if cortisol levels drop normally after taking a steroid medicine

What to expect at your appointment

You will have a blood sample taken from a vein in your arm. It is a quick procedure that takes only a few minutes. Your doctor may ask you to fast or avoid certain medications before the test. You can usually go back to normal activities right after.

Treatment

Treatment depends on whether your cortisol is too high or too low, and what is causing the imbalance. The goal is to bring cortisol levels back to normal and manage any underlying condition.

Self-care at home

• Follow your doctor's advice on medications and monitoring
• Manage stress with relaxation techniques like deep breathing or meditation
• Get enough sleep and keep a regular sleep schedule
• Stay hydrated and eat a balanced diet

Medical treatments

If cortisol is too high (Cushing's syndrome), treatment may include medications that lower cortisol production or block its effects, surgery to remove a tumor, or radiation therapy. If cortisol is too low (Addison's disease), doctors usually prescribe hormone replacement therapy with a synthetic form of cortisol, taken by mouth. The dose is adjusted to match your body's natural rhythm. Always follow your doctor's instructions and never change your dose without talking to them first.

When is surgery considered?

Surgery may be needed if a tumor in the pituitary or adrenal gland is causing the imbalance. Removing the tumor can often restore normal cortisol levels.

Living with this condition

With proper treatment, many people with cortisol imbalances can live active, healthy lives. You may need to take medication daily and have regular check-ups to monitor your hormone levels. Always keep an emergency supply of your medication in case you get sick or stressed.

Lifestyle tips

• Take your medications exactly as prescribed
• Wear a medical alert bracelet or carry an emergency card if you have adrenal insufficiency
• Monitor for signs of under- or over-replacement and report them to your doctor
• Avoid sudden stops of steroid medications without medical advice

Diet and exercise

A balanced diet with plenty of fruits, vegetables, and lean protein supports overall health. Regular exercise, like walking or swimming, can help manage weight and stress. Talk to your doctor before starting a new exercise program, especially if you have adrenal issues.

Mental health and emotional wellbeing

Cortisol imbalances can affect mood and energy levels, leading to anxiety, depression, or irritability. It is normal to feel frustrated or worried. Speak with your doctor or a mental health professional if you need support. You are not alone.

Prevention

Most causes of abnormal cortisol levels cannot be prevented. However, you can reduce your risk by avoiding unnecessary long-term use of steroid medications without medical supervision. Managing stress and leading a healthy lifestyle may also help keep your hormones balanced.

Complications

If left untreated

• If cortisol is too high (Cushing's syndrome): high blood pressure, type 2 diabetes, osteoporosis, frequent infections, and increased risk of blood clots
• If cortisol is too low (Addison's disease): adrenal crisis – a life-threatening condition with severe vomiting, low blood pressure, and confusion

Long-term outlook

With early diagnosis and proper treatment, most people with cortisol imbalances can manage their condition and lead full lives. Treatment is effective and can prevent complications. Your healthcare team will work with you to find the best plan.

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