Questions about False Positives in Drug Testing, page 188

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 we do not give medical or legal advice.

Saliva test
Date: 3/27/2012
I have a mouth swab test on Friday for my new job and I took cough medicine with Acetaminophen, Dextromethorphan and Doxylamine last night around 1 am… Is 72 hours enough for that to get out of my system so I don’t test positive at my saliva test?


AskDocWeb: Acetaminophen is out of your system within 24 hours and Doxylamine within 3 days. However, the “half-life” of Dextromethorphan could be up to 19.1 hours in poor metabolizers which means that it could persist for up to 4 days.

Date: 3/27/2012
How long does it take TASC to notify you if you dropped a dirty urine analysis?


AskDocWeb: We don’t know. Hopefully a reader will be able to help with this question.

I’m totally horrified by this
Date: 3/28/2012
I am prescribed Tramadol, Hydrocodone, Celexa, and Adderall. I didn’t know I wasn’t supposed to take anything else so I had a cough and took some pheneragen w/ codiene. My doc said my drug test was positive for the codeine AND Morphine and immediately dismissed me from the whole clinic and hospital he is affiliated with. I’m totally horrified by this. Could the Codeine make a false positive for the Morphine? I have NEVER taken Morphine. He had been prescribing my meds for 4 years and dismissed me without even talking to me. Does he really have the right to do this to me?


AskDocWeb: Acetaminoph with codeine has tested false positive for Morphine (Reference 1) so that may be a possibility. It sounds like you may have become another victim of the “War on Drugs.” Your loss of treatment is part of the consequences of treating people with drug addiction problems as if they are criminals instead of treating drug addiction as a health problem, which it really is.

In most cases a positive result on a urine drug test is legally considered “presumptive” which means that the chances of drug abuse are high enough that your doctor is justified in discontinuing service. Unfortunately it appears that doctors are not required to confirm those results.

Tested positive for THC and methamphetamine
Date: 3/28/2012
I have been using albuterall for 20 years as needed. I also take adderall daily for ADD. I recently had surgery on my shoulder and do not know everything they gave me, but I was given Hydrocodone 10 afterwards and was using that quite a bit the day leading up to my UA which I took only a week and a half after surgery. I expected to show up possitive for opiates and methamphetamine as that is what I am presribed, but instead tested positive for THC and methamphetamine. Why would THC show up and not the hydrocodone?


AskDocWeb: The answer may lie in the unknown things that they gave you for the surgery however, there are over 70 substances that might test positive for THC and about 50 substances that may test false positive for methamphetamine on urine tests. None of the other meds you mention are known to cause this.

What can cause a false positive for Phenobarbital?
Date: 3/28/2012
Hi this isn’t for me this is for my girlfriend who was just arrested for a false positive drug test that said she had Phenobarbital in her system this is the second time that it came back positive in the past two months. So here is my question what can cause a false positive for Phenobarbital? Please help me.


AskDocWeb: According to The Encyclopedia of Addictive Drugs Fiorinal is known to produce a false positive for phenobarbital in body fluid testing.

Positive for barbiturates
Date: 3/29/2012
Hi, my name is Ann. I took a urine drug test at work and it come back positive for barbiturates. The thing i have taken in the last couple weeks is phentermine 37.5 I dont understand this positive for barbiturates.


AskDocWeb: Phentermine has been reported to sometimes cause a false positive for amphetamines or ecstasy on urine tests but not barbiturates. You might check this list to see if you are taking anything else that might explain it.

False positive for opiates?
Date: 3/29/2012
Can the combination of Ranitidine and Tylenol PM containing diphenhydamine cause a false positive for opiates?


AskDocWeb: Ranitidine might show up as a false positive for amphetamines or methamphetamines but not opiates. Likewise products containing diphenhydramine have tested positive for Tricyclic Antidepressants (TCA) but not opiates. A few of the Tylenol products have been reported to show up as a false positive for opiates.

Bodybuilding supplements?
Date: 3/29/2012
I just failed a UA. Can I show up false positive by taking Bodybuilding supplements? It was for PCP and thc I dont do drugs.


AskDocWeb: Which bodybuilding supplements are you taking? It is okay to name names here. If a particular supplement might cause a false positive other bodybuilders want to know that.

Failed a probation drug test
Date: 3/29/2012
I recently fail a probation drug test. It had been close to 4 months since I had knowingly consumed thc. Before that. Day it had been 13 months….kinda scared


Date: 3/29/2012
I have a client who is testing positive for methamphetamines/amphetamines. Can his taking of flomax be causing this?


AskDocWeb: Flomax has not been reported to cause any type of false positive on urine drug tests for drugs of abuse.

Having sex with someone who uses meth
Date: 3/29/2012
What otc drugs also i take cholesterol medicine and sinus meds by prescription can make you test positive for meth in the urine only because none was found in blood? Also can you test positive for meth after having sexual intercourse with some one who had recently used meth?


AskDocWeb: There are about 50 substances that might cause a false positive for meth on a urine drug screen. There are listed on the false positive list. Meth can be absorbed through the skin so it is theoretically possible but we haven’t seen any reports of that happening.

Don’t chance a false positive
Date: 3/30/2012
I wanted to ask if any of the following could show up in a drug test as a false positive: GNC Amino Acid Formula, Rhodiola Rosea, Essential Fatty Acids, Women’s daily multi vitamin and L-Glutamine. These are the supplements I am taking and I don’t want to chance them showing up as a false positive. Thanks,


AskDocWeb: It looks like you are in good shape there. None of those have been reported to cause any problems with urine drug tests.

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