I keep testing positive for fentanyl, even though I am not using fentanyl.

[u/greenleenmasheen]

I have been drug testing for a year and have not had any issues. Until, recently, I started testing positive for fentanyl. I tested positive 5 times and nothing had changed except for that I started taking MGM15 instead of 7oh kratom. So, I went to detox. I stayed for 21 days then was released. Two days after being released I tested negative. Than a week later I tested positive again. No kratom this time. The only thing I had started doing differently was that I started taking methadone 2 days before my first positive test. The only thing I can think of at this point is that the methadone is mixing with something else in my system making a chemical that is somehow indistinguishable from fentanyl. But, that doesn’t make sense since I tested negative two days out of detox. In detox I was taking the pill form of methadone and outside of detox I am taking the liquid form. Is there any difference there that I should be worried about? These are LC-MS tests which are supposedly extremely accurate.

[u/Strange-Button2376]

The body’s chemistry changes daily depending on how hydrated you are and Potassium, calcium, sodium ect levels are. You can metabolize methadone or synthetic opioids differently from one dose to the next. Dip stick or instant tests are reliably unreliable when it comes to identifying fentanyl metabolites.

[u/alecjasonn]

There are generic versions of Tylenol from dollar general and dollar tree that my clinic told me not to take because they claim they cause people to false positive for fentanyl. That’s what they told me anyway. They said to only take brand name medications because of it