How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask A. Schuyler, NP Your Own Question
A. Schuyler, NP
A. Schuyler, NP, Nurse Practitioner
Category: Health
Satisfied Customers: 15925
Experience:  Board Certified NP, MS, RN. 25 years private practice & hospitalist
Type Your Health Question Here...
A. Schuyler, NP is online now
A new question is answered every 9 seconds

What prescription drug would cause a false positive for fentanyl

Resolved Question:

What prescription drug would cause a false positive for fentanyl? I haven't had any since surgery 7 years ago.
Submitted: 7 years ago.
Category: Health
Expert:  A. Schuyler, NP replied 7 years ago.



Welcome to Just Answer and thanks for your question. If this was a lab test via GC/MS (gas chromatography/mass spectrophotometry) there is nothing that will cause a false positive. I am assuming this is the kind of test it was, since screening tests are only positive for opiates without specifying which opiate. It would take GC/MS testing to differentiate between Fentanyl and oxycodone, for instance.


In a dipstick-type screening test there are a number of things that might cause a false positive like lots of poppyseed bagels, most prescription pain medications, cough suppressants with dextromethorphan, etc. However, a screening positive is supposed to be sent to the lab for confirmation testing via GC/MS to determine the exact nature of what is causing the positive. There are no false positives or false negatives with the GC/MS tests.


Customer: replied 7 years ago.
I don't see how fentanyl could be in my system 7 years later?
Expert:  A. Schuyler, NP replied 7 years ago.

No, Fentanyl won't be in your system 7 years later, or even 7 weeks later. Perhaps someone has played a sick trick on you.


A. Schuyler, NP and 5 other Health Specialists are ready to help you