7 doctors weighed in:
What substances interfere with the plasma metanephrine test? 
7 doctors weighed in

Dr. Pedro Hernandez
Internal Medicine - Geriatrics
3 doctors agree
In brief: Metanephrine
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 coll.

In brief: Metanephrine
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 coll.
Dr. Pedro Hernandez
Dr. Pedro Hernandez
Thank
Dr. Terry Woodard
Internal Medicine - Nephrology & Dialysis
2 doctors agree
In brief: Many substances
The assay for free metanephrines is sensitive, but not specific.
Many drugs containing Epinephrine compounds (such as sudaphed and related ones), as well as some anti-depressants (especially mono amine oxidase inhibitors) will affect the results. Tyrosine containing foods (bananas, cheese, etc.) often interfere with levels, as does smoking, some local anesthetics and Acetaminophen may as well.

In brief: Many substances
The assay for free metanephrines is sensitive, but not specific.
Many drugs containing Epinephrine compounds (such as sudaphed and related ones), as well as some anti-depressants (especially mono amine oxidase inhibitors) will affect the results. Tyrosine containing foods (bananas, cheese, etc.) often interfere with levels, as does smoking, some local anesthetics and Acetaminophen may as well.
Dr. Terry Woodard
Dr. Terry Woodard
Thank
Get help from a real doctor now
Dr. William Forsythe
Board Certified,
23 years in practice
171K people helped
Continue
107,000 doctors available
Read more answers from doctors