False-Positive Fentanyl Drug Test Due To Invega

Answer

Thanks for reaching out! This is a topic we have covered before (one of our prior answers can be found here) and there is certainly published data showing that both risperidone and Invega (paliperidone) can cause false-positive drug tests for fentanyl.

While I don't know of an official government record, the manufacturer of Invega specifically discusses the topic on their official website for the drug, and studies on the topic are published on PubMed, which is maintained by the United States National Library of Medicine at the National Institutes of Health.

Janssen, the manufacturer of Invega, states the following

During a validation study, risperidone and its active metabolite, 9-hydroxy-risperidone (paliperidone - INVEGA), were found to cross-react with the DRI® fentanyl immunoassay. The authors concluded that a similar chemical moiety (3-methyl-5-piperidino-2-pentene) that is shared with fentanyl and acetylfentanyl may be recognized by the antibody for the immunoassay.

The authors of the study that is referenced in the excerpt above recommend that anyone taking risperidone or Invega who tests positive for fentanyl take a confirmatory test to validate (or prove false) the results.

Why Can A False-Positive Happen?

False positives can, unfortunately, happen on immunoassay drug tests simply based on how these tests work.

Essentially, immunoassay-based tests rely on antibodies to react with specific drugs (or drug metabolites) in a given sample. Sometimes, antibodies react with the wrong drug, and when the test shows a reaction occurred, it can be marked as a positive reading for a different drug than intended.

How often false-positives occur in the testing population isn't known, but it certainly is a well-established event that can happen and is discussed in most studies that discuss drug testing.

Final Words

I highly suggest you provide the information I have written about here, along with the study I referenced above, with whoever you need to. This information is publicly available and published in respected academic journals. The links are in the 'references' section at the bottom of this answer.

It is well established that Invega can cause false-positives for fentanyl, and due to the repercussions a positive drug test can have, I would hope you have the opportunity to take another test or have a confirmation test done.