Fractionated Plasma Free Metanephrines Test- Why am I having this test?
The fractionated plasma-free metanephrines test is used to screen for a type of adrenal gland tumor called pheochromocytoma. You may have this test if you have symptoms of pheochromocytoma or a family history of this type of tumor.
What is being tested?
This test measures the amount of metanephrine and normetanephrine in your blood. Metanephrine and normetanephrine are substances that appear in your blood after adrenaline and other hormones break down. Increased levels of these substances in your blood may be a sign of having a pheochromocytoma tumor.
What kind of sample is taken?
A blood sample is required for this test. It is usually collected by inserting a needle into a blood vessel.
How do I prepare for this test?
- Tell a health care provider about all medicines you are taking, including vitamins, herbs, eye drops, creams, and over-the-counter medicines. You may have to stop taking some medicines 1–2 weeks before the test.
- Avoid taking acetaminophen for 48 hours before the test.
- Avoid activities and exercises that take a lot of effort for a few days before the test.
- Do noteat or drink anything for 8 hours before the test or as told by your health care provider.
- Do notdrink alcohol or consume foods or drinks that contain caffeine for as long as told by your health care provider before the test.
- Do notuse any products that contain nicotine or tobacco, such as cigarettes and e-cigarettes, for 4 hours before the test.
How are the results reported?
Your test results will be reported as values. They may be reported as picograms per milliliter (pg/mL) or nanomoles per liter (nmol/L). Your health care provider will compare your results to normal ranges that were established after testing a large group of people (reference ranges). Reference ranges may vary among labs and hospitals. For this test, common reference ranges are:
- 18–111 pg/mL or less than 0.5 nmol/L for normetanephrine.
- 12–60 pg/mL or less than 0.9 nmol/L for metanephrine.
What do the results mean?
If your results are within the normal range, it is unlikely that you have a pheochromocytoma.
If your results are above the normal range, your health care provider may repeat the test. You may also have other tests that help diagnose pheochromocytoma. These may include urine tests and imaging studies.
Talk with your health care provider about what your results mean.
Questions to ask your health care provider
Ask your health care provider, or the department that is doing the test:
- When will my results be ready?
- How will I get my results?
- What are my treatment options?
- What other tests do I need?
- What are my next steps?
Summary
- The fractionated plasma-free metanephrines test is used to screen for a type of adrenal gland tumor called pheochromocytoma.
- This test measures the amount of metanephrine and normetanephrine in your blood. Increased levels of these substances in your blood may be a sign of having a pheochromocytoma tumor.
- If your results are within the normal range, it is unlikely that you have a pheochromocytoma.
- If your results are above the normal range, your health care provider may repeat the test and perform other tests that help diagnose pheochromocytoma.
