Catecholamines - blood

Definition

Catecholamines are hormones produced by the adrenal glands, which are found on top of the kidneys. They are released into the blood during times of physical or emotional stress. The major catecholamines are dopamine, norepinephrine, and epinephrine (which used to be called adrenalin).

This article discusses the test to check the level of catecholamines in a sample of blood.

Catecholamines are more often measured with a urine test than with a blood test. See: Catecholamines - urine

Alternative Names

Norepinephrine - blood; Epinephrine - blood; Adrenalin - blood; Dopamine - blood

How the test is performed

Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.

Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.

How to prepare for the test

The accuracy of the test can be affected by certain foods and drugs, as well as physical activity and stress.

Foods that can increase catecholamine levels include:

• Coffee
• Tea
• Bananas
• Chocolate
• Cocoa
• Citrus fruits
• Vanilla

You should avoid these foods for several days prior to the test, particularly if both blood and urine catecholamines are to be measured.

You should also avoid stressful situations and vigorous exercise, which can both interfere with test results.

Drugs that can increase catecholamine measurements include:

• Aminophylline
• Caffeine
• Chloral hydrate
• Clonidine
• Disulfiram
• Erythromycin
• Insulin
• Levodopa
• Lithium
• Methenamine
• Methyldopa
• Nicotinic acid (large doses)
• Nitroglycerin
• Quinidine
• Tetracycline

Drugs that can decrease catecholamine measurements include:

• Clonidine
• Disulfiram
• Guanethidine
• Imipramine
• MAO inhibitors
• Phenothiazines
• Reserpine
• Salicylates

Never stop taking any medication without first talking to your doctor.

How the test will feel

Some people feel discomfort when the needle is inserted. Others may notice only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed

This test is used to diagnose or rule out a pheochromocytoma or neuroblastoma. It may also be done in patients with those conditions to determine if treatment is working.

Normal Values

Epinephrine: 0-900 picograms/milliliter (pg/ml)

Norepinephrine: 0-600 pg/ml

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

What abnormal results mean

Higher-than-normal levels of blood catecholamines may suggest:

• Acute anxiety
• Ganglioblastoma (very rare)
• Ganglioneuroma (very rare)
• Neuroblastoma (rare)
• Pheochromocytoma (rare)
• Severe stress

Additional conditions under which the test may be performed include Shy-Drager syndrome.

What the risks are

There is very little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

Special considerations

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References

Young WF Jr. Adrenal medulla, catecholamines, and pheochromocytoma. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 246.

Guber HA, Farag AF, Lo J, Sharp J. Evaluation of endocrine function. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. Philadelphia, Pa: Saunders Elsevier; 2006:chap 24.