Plasma Free Metanephrine

To help diagnose or rule out a pheochromocytoma

When you have persistent or episodic high blood pressure and symptoms such as headaches, rapid heart rate, and sweating

A blood sample drawn from a vein in your arm

Preparation for the test is important for accurate results. You should discontinue epinephrine and epinephrine-like drugs for at least 1 week before the test, stop using acetaminophen 48 hours beforehand, and fast for 8-10 hours prior to collection. It is especially important not to have any caffeine containing food (soda, chocolate), coffee (including decaf), tobacco (smoking cigarettes or cigars), tea, or alcohol for at least 4 hours before specimen collection. Talk to your doctor about all the medications you are taking as well since several different drugs may interfere with the test.