Questions about False Positives in Drug Testing, page 226

False Positives Forum

This forum is intended to help those who Do NOT Abuse Drugs. We do NOT support the illegal use of any substance. If you have experience with false positives, share your experience. What would you tell someone about drug testing and false positives? Please remember that this forum is not for medical or legal advice.

What do I tell the lab people?
I take 16mg. of subutex and alteril and walsom sleep aids otc. the subutex i get legally, I had a oral swab drug test for a new job 3 hours after dose, will i fail the test for this, and what do i tell labs people when they call to question me if it does fail.


AskDocWeb: If that is all you took then you will likely pass the test. If for some reason you get a call about failing, tell them what you are taking and that you want a confirmation test from an independent laboratory that is certified by SAMHSA. That’s the government agency that sets federal standards for drug testing.

Lost job opportunity
Sure would have been nice to know all this two or three days before I lost a good job opportunity due to my over-the-counter use of both zantac and ibuprofen(meth and marijuana). Why can’t I sue someone? Know a good lawyer?


AskDocWeb: To find out if you may have a case or not there are Lawyers online that you can ask.

What medicines can interfere with a urine test?
My aunt has been on xanax for over 20 years she is on a lot of other medications her doctor drug tested her and it came back negative for Xanax. How is this possible and what medicines can interfere with a urine test?


AskDocWeb: If the drug test was done too long after the Xanax was taken, there may not have been enough left in her system to show up on the test. Also although errors are not as rare as we would like, they do happen. According to Dr. Carolyn Clancy, “We’ve learned as a result of a groundbreaking report from the Institute of Medicine that up to 98,000 people a year die as a result of medical errors. And many, many people believe that that’s an under-estimate. The reason they think it may actually be a low figure is because that only includes estimates for problems that occur in the hospital.” (Source: That does not include errors made in doctor’s offices, nursing homes, clinics, rehab facilities and so forth.

There are hundreds of medicines that can interfere with urine tests. See this list.

False positive for Benzodiazipines?
Can any one or all of Ultram, Ibuprofen, Naproxyn cause a false positive urine drug screen for Benzodiazipines?


AskDocWeb: Of those, only Naproxyn has been reported to show up as false positive on urine drug screens. According to Lawyers And Settlements (Online Legal Media), anti inflammatory drugs such as Naproxyn may test false positive but they don’t say which drugs might be cross-reactive with them.

I tested positive for opiates and the only thing ive taken is zyprexa can it cause this positive test?


AskDocWeb: Zyprexa does not show up on standard drug tests and they typically do not test for it.

Tested positive for meth and amphetamines during a ua for court. I do not use street drugs, absolutely despise meth addicts and actually would prob die if I did use the drug because I have a serious blood clotting disorder. I do however take 15 mg Adderall XR daily and this weekend had a horrible head cold. I took Wal-Phed around the clock as well as some (prescription) trazadobe. I’ve done enough searching to know that wal phed is the culprit. I want to retest myself before court next week but want to know how long I should wait so I can avoid another false positive. Or will a lab test be able to tell the difference. I want to do it as soon as possible Thank you. The first test was a urine sample that I was told to dump out after so unfortunately I can’t have that sample tested.


AskDocWeb: We agree with your assessment of Wal-Phed. It contains pseudoephedrine hcl, which could show up on a urine test. Since the serum half-life for pseudoephedrine is 6 to 8 hours it could take a couple of days to completely leave your system. That is for those with a healthy elimination system. Any liver or kidney problems may extend that time. If you do fail the urine test because of the Wal-Phed, a confirmation test will rule out that false positive. Good luck.

Prazosin, taking this for PTSD nightmares. I have mandatory testing for THC nanograms in urine, after several months of not using marijuana, I have had one clean test, also using Aleve, positive results have occurred, although reduced consumption of Aleve. Will Prazosin cause false positives for THC?


AskDocWeb: No, the only place where Prazosin (Minipress) has shown up in the research on false positives was in specific screening tests for pheochromocytoma.

I have never taken tramado and it showed traces of it in my urine, what causes this. I am on gabapentin, advair, provental, serequel, effexor xr, hydrocodone, and another inhaler, I can’t think of the name off hand. Can any of these cause it


AskDocWeb: Tramado is one of the common misspellings of tramadol. Our database

does not show any substance that might be mistaken for tramadol. However, we want to thank you very much for the question because in researching an answer for you it was discovered that tramadol (Ultram) has shown up as a false positive for PCP (phencyclidine). That is according to Michael E. Mullins, M.D., Medical Toxicologist at the Washington University in St. Louis.

Tested positive for K2
My husband takes Strattera 80MG a day and Paroxetine HCL 20MG a day and at a recent drug test tested positive for K2? Until explained we did not even know what K2 was. Can these two medications together cause a fales positive?


AskDocWeb: Neither of those medications are known to cause a false positive on urine drug tests for any drugs of abuse. As for an explanation, that is going to be difficult. The tests for K2 are relatively new and to date there are no known causes for a false positive. However, that does not rule out that possibility. The way to determine if it is a false positive result is to have a confirmation test done at an independent laboratory. Currently the Gas Chromatography/Mass Spectrometry (GC/MS) test is the “gold standard” in drug testing because it positively identifies the presence of a particular substance in a given sample.

Chemicals used on golf courses
Are there any chemicals used on golf courses that could make a drug test come up positive for benzodiazepines?


AskDocWeb: Sorry Sara, we do not have a list of all the possible chemicals used on golf courses. IF you are concerned about a specific chemical you can look it up here.

Popping positive for methamphetamine!
My wife has been to 3 doctors. She has a dislocated hip and is in quite a bit of pain. She has never used illegal drugs, but she keeps popping positive for methamphetamine! She takes Zanaflex and Neurontin regularly and takes OTC pain relievers. Why is this happening?


AskDocWeb: Something she is taking, not the Zanaflex or Neurontin, may be cross-reacting on the urine test. A false positive for methamphetamine is most often caused by allergy, asthma, and diet medications but other causes are also possible. You would need to get a confirmation test (GC/MS) in order to show her doctors that her test result is a false positive.

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