Test Overview

A test for catecholamines measures the amount of the hormones epinephrine, norepinephrine, and dopamine in the blood. These catecholamines are made by nerve tissue, the brain, and the adrenal glands. Catecholamines help the body respond to stress or fright and prepare the body for "fight-or-flight" reactions.

The adrenal glands make large amounts of catecholamines as a reaction to stress. The main catecholamines are epinephrine (adrenaline), norepinephrine (noradrenaline), and dopamine. They break down into vanillylmandelic acid (VMA), metanephrine, and normetanephrine. Metanephrine and normetanephrine also may be measured during a catecholamine test.

Catecholamines increase heart rate, blood pressure, breathing rate, muscle strength, and mental alertness. They also lower the amount of blood going to the skin and intestines and increase blood going to the major organs, such as the brain, heart, and kidneys.

Certain rare tumours (such as a pheochromocytoma) can increase the amount of catecholamines in the blood. This causes high blood pressure, excessive sweating, headaches, fast heartbeats (palpitations), and tremors.

Why It Is Done

A catecholamine test is done to help diagnose a tumour in the adrenal glands called a pheochromocytoma. Catecholamine levels in the blood can change quickly, so it may be hard to find high values in a single blood sample. But a special compound, metanephrine, may be found in the blood, which may mean a pheochromocytoma is present. Doctors may want to do a urine test that measures catecholamine levels over 24 hours.

How To Prepare

You may be asked to avoid certain foods and fluids for 2 to 3 days before having this test, such as:

• Caffeine, such as coffee, tea, cocoa, and chocolate.
• Amines. These are found in bananas, walnuts, avocados, fava beans, cheese, beer, and red wine.
• Any foods or fluids with vanilla.
• Licorice.
• Aspirin.

You may be asked to not eat or drink anything for 10 hours before this test. Do not use tobacco for 4 hours before the blood test.

Your doctor may ask you to stop certain medicines, such as blood pressure medicines, before the test. Do not take cold or allergy remedies, including aspirin, or non-prescription diet pills for 2 weeks before the test.

Having a blood sample taken can cause stress. This may increase catecholamine levels. Be sure to keep warm, because being cold can also increase your levels. Ask for a blanket if you feel cold.

How It Is Done

A health professional uses a needle to take a blood sample, usually from the arm. Or they may insert a small tube into your vein and have you rest for 30 minutes before the blood sample is taken.

Watch

How It Feels

When a blood sample is taken, you may feel nothing at all from the needle. Or you might feel a quick sting or pinch.

Risks

There is very little chance of having a problem from this test. When a blood sample is taken, a small bruise may form at the site.

Results

Normal

Each lab has a different range for what's normal. Your lab report should show the range that your lab uses for each test. The normal range is just a guide. Your doctor will also look at your results based on your age, health, and other factors. A value that isn't in the normal range may still be normal for you.

High values

• High levels of catecholamines, vanillylmandelic acid (VMA), or metanephrine can mean that an adrenal gland tumour (pheochromocytoma) or another type of tumour that makes catecholamines is present.
• Any major stress, such as burns, a whole-body infection (sepsis), illness, surgery, or traumatic injury, can cause high catecholamine levels.
• Many blood pressure medicines can also cause high catecholamine levels.

Low values

Low levels of catecholamines usually do not indicate a problem.