Catecholamines - blood
Definition
The blood test for catecholamines checks the level of catecholamines in your blood. 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).
See also: Catecholamines - urine
Alternative Names
Norepinephrine - blood; Epinephrine - blood; Adrenalin - blood; Dopamine - bloodHow the Test is Performed
Catecholamines are more often measured with a urine test than with this blood test.
Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic. An elastic band is placed around the upper arm to apply pressure and cause the vein to swell with blood.
A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. 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, the area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. A bandage may be applied to the puncture site 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 Results
Normal value ranges may vary slightly among different laboratories.
Epinephrine: 20 ng/100 mL (ng/mL = nanograms per milliliter)
Norepinephrine: 60 ng/100 mL
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
Risks
- Excessive bleeding
- Fainting or feeling light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
- Multiple punctures to locate veins
Considerations
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult from some people than from others.
Reviewed By: Benjamin W. Van Voorhees, MD, MPH, Assistant Professor of Medicine and Pediatrics, The University of Chicago, Chicago, IL. Review provided by VeriMed Healthcare Network.
