This test measures the levels of catecholamines in your urine.
Catecholamines are hormones made by your adrenal glands and released when you have physical or emotional stress. These hormones, which include epinephrine and dopamine, have many functions in the body, from transmitting nerve impulses in the brain to constricting blood vessels and increasing your heart rate.
People who have a rare type of tumor called a pheochromocytoma have high levels of catecholamines in their urine. These tumors cause high blood pressure that generally goes away if the tumor is taken out. About 95 percent of these tumors are found in the abdomen.
You may need this test if your doctor suspects that you have a pheochromocytoma tumor. Signs and symptoms may include:
High blood pressure
Not everyone with this type of tumor has high blood pressure. Five to 15 percent of people with this type of tumor have normal blood pressure.
Other symptoms include heart palpitations, weakness, and symptoms similar to those of a panic attack. Less common symptoms include blurry vision and weight loss.
You might also have this test if you have high blood pressure that doesn't respond to conventional treatment.
Your doctor may also order other tests, including:
CT or MRI scan
Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your health care provider.
Results are given in micrograms per 24 hours (mcg/24 hour). Normal results are:
Norepinephrine: less than 170 mcg/24 hour
Epinephrine: less than 35 mcg/24 hour
Dopamine: less than 700 mcg/24 hour
Normetanephrine: less than 900 mcg/24 hour, or metanephrine: less than 400 mcg/24 hour
Higher levels of these hormones may mean you have a pheochromocytoma tumor.
This test requires a 24-hour urine sample. For this type of sample, you must collect all the urine you produce for 24 hours. Empty your bladder completely first thing in the morning without collecting it and note the time. Then collect your urine every time you go to the bathroom for the next 24 hours.
The test poses no known risks.
Certain medications, including tricyclic antidepressants and cold and allergy drugs, can affect your results.
These foods can also affect your results:
Coffee, including decaffeinated coffee
Vanilla, including foods and beverages that contain vanilla
Oranges and other citrus fruits
Beer and red wine
Your doctor may ask you to stop taking tricyclic antidepressant medication at least two weeks before the test. Never abruptly stop your medications before talking with your doctor. He or she may recommend a gradual decrease in the amount of medication your take.
You should avoid the foods listed in the previous section before and during the test. Try to avoid stressful situations, vigorous exercise, and getting cold before the test. Don't use tobacco before the test.
In addition, be sure your doctor knows about all other medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use.