False + on drug screen

[cb_rn]

Interesting fact I just found out...maybe I was asleep in school the day we covered this... but it seems there are a few docs and labs that don't know this either

protonix can create a false positive on your urine drug screen for THC

wellbutrin can create a false postive for amphetamines

anyone ever have this happen to them? and is this common knowledge?

UPDATE: I decided to google this and found an interesting link. WOW.

http://www.askdocweb.com/falsepositives.html

[cmonkey]

I'd think if you listed those meds on your forms, they'd take that into account.

[chenoaspirit, ASN, RN]

I agree that they should take that into account, but I had NO idea those drugs would do that! wow.

[cb_rn]

I'd think if you listed those meds on your forms, they'd take that into account.

I would have thought so as well. Evidently not.

Actually this little tibit of knowledge came back from someone who tested postive demanding to see the physician and the lab supervisor. The lab called the reagent manufacturer and that's how it was all clarified.

So that was my *interesting* find of the day.

[MERRYWIDOW46]

My area of the country we are no longer permitted to list medications we are prescribed prior to urine tox. ONLY if we test positive for something. I once tested positive from poppy seed bagel, they did a more detailed test on same specimen and was negative.

[Orca, ADN, ASN, RN]

The list of medications that can cause false positives on drug screens is lengthy, and it even includes some OTC medications - which many people wouldn't remember to mention if taking a drug screen.

[MaryEMT]

While it initially may cause a positive results a more detailed drug screen would reveal the truth (medications vs. drugs). I work at a drug rehab facility and we routinely screen for drugs whenever a client comes back from a pass. There are a lot of co-occuring disorders and there are ALOT of clients on Welbutrin. There amphetamines reflect accurate results (mostly negative and positive when amphetamines were taken recreationally).

[Penelope_Pitstop, BSN, RN]

As for that link, it's weird that it lists Extra Strength Tylenol as "false positive for Acetaminophen." I don't know what's so, well, FALSE, about that one...

[cb_rn]

I have no doubt you can distinguish a false + from a true one with some investigation. I just think its interesting. Especially that there are so many common drugs on that link I posted above (which is probably not all inclusive) and that neither the doctor nor the lab supervisor were aware in this particular instance.

BTW I'm not laying blame on either of them, in fact I give kudos to the lab supervisor for following up instead of just assuming the patient was lying. Wonder how many times a patient's insistence that they were clean has fallen on deaf ears?

Also makes me wonder how many people have failed a drug screen and lost a job employment offer.

Surely it isn't that common because you'd think if it were there would be more people protesting that drug tests are bunk (if they had no knowledge that there was a such thing as false positives and just assumed some crazy pee test was saying they were a drug user when they knew they were not). I can see where something like a false + could make a patient very suspicious of medical/lab tests, especially if they didn't have a good practitioner willing to investigate further if the patient was adamant he or she hadn't taken any illegal substances

[cb_rn]

As for that link, it's weird that it lists Extra Strength Tylenol as "false positive for Acetaminophen." I don't know what's so, well, FALSE, about that one...

haha yeh - that is pretty strange, I didnt do a lot of investigation on the site, it was one of the first things that popped up in my google search just to give a relative idea of the different things that may cause a positive. I don't know how accurate that site is but I'm sure there is a reliable site that has good references.

I was just curious because a friend that works in the ER mentioned this to me and I it struck me as interesting that nobody just "knew" this out without investigation. I know protonix is pretty common drug, I would have thought it would be common knowledge if it routinely influenced a urine drug screen.

[november17, ASN, RN]

Tonic water can cause a false positive for cocaine. I had a job interview last summer and I got the job; they wanted me to come do a physical drug/test the next day. I was so I happy that I celebrated by going to a bar and having a few gin and tonics. I didn't test positive, but I spent a few days afterwords scared to death that I blew the drug test after the bartender told me that. Something about the metabolic leftovers from tonic water or quinine; I can't remember.

[DogCrazy]

I worked in a forensic laboratory for years before starting nursing school. Any positive results should be confirmed by GC/MS, and that would determine exactly what was in the urine. The false positives are from the screening tests only, not the confirmations, at least at our lab. We used to have probationers claiming a false positive from alllll kinds of stuff, but when you find a metabolite in urine that is specific only to cocaine, that there's a positive drug screen.