Catecholamines, Plasma and Urine

This is a test used to evaluate persistent or episodic high blood pressure, severe headaches, rapid heart rate, and sweating. Catecholamines are a group of similar hormones produced in the medulla (central portion) of the adrenal glands. The primary catecholamines are dopamine, epinephrine (adrenaline), and norepinephrine. These hormones are released into the bloodstream in response to physical or emotional stress. They help transmit nerve impulses in the brain, increase glucose and fatty acid release (for energy), dilate bronchioles (small air passages in the lungs), and dilate the pupils. Norepinephrine also constricts blood vessels (increasing blood pressure) and epinephrine increases heart rate and metabolism.

Urine and plasma catecholamine testing can be used to help detect the presence of pheochromocytomas and paragangliomas. It is important to diagnose and treat these rare tumors because they cause a potentially curable form of hypertension. In most cases, the tumors can be surgically removed and/or treated to significantly reduce the amount of catecholamines being produced and to reduce or eliminate their associated symptoms and complications.

Catecholamine testing measures the amount of epinephrine, norepinephrine, and dopamine in the plasma or urine. (The metabolites of these hormones may be measured separately with a urine metanephrine and/or VMA test). The plasma catecholamine test measures the amount of hormones present at the moment of collection, while the urine test measures the amount excreted over a 24-hour period.

PREPARATION FOR TEST

A blood sample drawn from a vein in the arm or a 24-hour urine sample is collected.

For the 24-hour urine collection, all of your urine should be saved for a 24-hour period. It is important that the sample be refrigerated during this time period. Since diet, exercise, and drugs may affect catecholamine levels, precautions need to be taken to assure that the sample reflects a true metabolic condition and not an interference or aberration. For this reason you should talk to your caregiver about your diet and any medications you are taking. Foods such as coffee (including decaf), tea, chocolate, vanilla, bananas, oranges and other citrus fruits should be avoided for several days prior to the test and during collection. There are also many medications that can potentially affect test results. Talk to your caregiver about the prescriptions and over the counter drugs and supplements that you are taking. Wherever possible, those that are known to interfere should be discontinued prior to and during sample collection. Emotional and physical stresses and vigorous exercise should be minimized prior to and during test collection as they can increase catecholamine secretion. For urine collection tests in females, tell the person doing the test if you are menstruating on the day the test is done.

NORMAL FINDINGS

VMA

  • Adult/elderly: Less than 6.8 mg/24 hr or <35 micromole/24 hr (SI units)

  • Adolescent: 1-5 mg/24 hr

  • Child: 1-3 mg/24 hr

  • Infant: Less than 2 mg/24 hr

  • Newborn: Less than 1 mg/24 hr

Catecholamines

  • Free Catecholamines

  • Less than 100 mcg/24 hr or <590 nmol/day (SI units)

Epinephrine

  • Adult/elderly: Less than 20 mcg/24 hr or <109 nmol/day (SI units)

  • Child:

  • 0-1 years: 0-2.5 mcg/24 hr

  • 1-2 years: 0-3.5 mcg/24 hr

  • 2-4 years: 0-6 mcg/24 hr

  • 4-7 years: 0.2-10 mcg/24 hr

  • 7-10 years: 0.5-14 mcg/24 hr

Norepinephrine

  • Adult/elderly: Less than 100 mcg/24 hr or Less than 590 nmol/day (SI units)

  • Child:

  • 0-1 years: 0-10 mcg/24 hr

  • 1-2 years: 0-17 mcg/24 hr

  • 2-4 years: 4-29 mcg/24 hr

  • 4-7 years: 8-45 mcg/24 hr

  • 7-10 years: 13-65 mcg/24 hr

Dopamine

  • Adult/elderly: 65-400 mcg/24 hr

  • Child:

  • 0-1 year: 0-85 mcg/24 hr

  • 1-2 years: 10-140 mcg/24 hr

  • 2-4 years: 40-260 mcg/24 hr

  • Greater than 4 years: 65-400 mcg/24 hr

Metanephrine

  • Less than 1.3 mg/24 hr or Less than 7 micromole/day (SI units)

Normetanephrine

  • 15-80 mcg/24 hr or 89-473 nmol/day (SI units)

Ranges for normal findings may vary among different laboratories and hospitals. You should always check with your doctor after having lab work or other tests done to discuss the meaning of your test results and whether your values are considered within normal limits.

MEANING OF TEST

Your caregiver will go over the test results with you and discuss the importance and meaning of your results, as well as treatment options and the need for additional tests if necessary.

OBTAINING THE TEST RESULTS

It is your responsibility to obtain your test results. Ask the lab or department performing the test when and how you will get your results.