Questions about False Positives in Drug Testing, page 268

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 test to rule out the false positives
Hello I was really concerned after seeing my doctor as I am in a pain contract with her and I know we do random urine test which I would expect but when the test came back positive for phentnayl. I am being re-tested but if it shows up again. I am not sure what to do. I have never taken phentnayl. I asked her what it was for she explained it. I am so worried and upset so I can only believe this is a false positive.

My doctor has me on Vicodin 5/500 only once or twic a day and only if needed. I told her all the other meds I was taking she said she has a list of those I also mention having oral surgery back in May and that do to being worried about this false positive drut I am very worried and concerned is there another test to rule out the false positive.


AskDocWeb: The test to rule out the false positives is usually the GC/MS confirmation test, which is short for Gas Chromatography/Mass Spectrometry. There are other confirmation tests such as the liquid chromatography tandem mass spectrometry (LC/MS/MS) but GC/MS is the gold standard for drug testing.

Depo medrol
Will 1 depo medrol shot 20 days ago show up on a DOT hair folicle drug test?


AskDocWeb: In researching your question we ran into the snow job caused by the War on Drugs. When the United States Department of Transportation was asked, “Is there a list of prohibited drugs for being medically qualified to drive a commercial motor vehicle (CMV)?” it appears that they did not give an honest answer. Older Americans would call it a “baffle them with bullshit” response (See for yourself here).

Their answer: “Section 391.41(b)(12) states: A person is physically qualified to drive a CMV if that person does not use a controlled substance identified in 21 CFR 1308.11, Schedule I, an amphetamine, a narcotic, or any other habit-forming drug. Exception: A driver may use such a substance or drug, if the substance or drug is prescribed by a licensed medical practitioner who is familiar with the driver’s medical history and assigned duties; and has advised the driver that the prescribed substance or drug will not adversely affect the driver’s ability to safely operate a CMV. This exception does not apply to methadone.”

That response is politically correct for the War on Drugs but it is not an answer to the question. If any reader finds a link to the “21 CFR 1308.11” list of controlled substances please let us know so that it can be made public.

Will methyl-cellulose show a false positive on a drug screen?
Need to know I take b complex, will methylcellulose show false for meth?


AskDocWeb: Methyl cellulose is a synthetic bulk-forming laxative used for treating constipation, obesity, and for managing chronic diarrhoea in bowel disease. It is also used in manufacture of capsules in nutritional, as a food additive, and as a coating for pharmaceutical products. Despite the “meth” in its name, It has not been reported to cause any problems with drug testing for drugs of abuse. Methylcellulose is freely available over the counter in the form of tablets. It is also the main ingredient in K-Y Jelly.

He had to let me go
I just recently tested positive for ritalin and oxycodone…i have taken at least 300 drug tests and never had an issue and my pain management doctor called me at 10pm friday and said he had to let me go…I am prescribed opana er, opana ir(was switched from oxycodone 20mg 26 days prior to test), topamax, noritriptilyn, and adderral…

I have never done anything other than what I’m prescribed and even turn in remaining when I have leftovers…I dont know what to do, without the combination of these meds I cant even walk and I’ve been with this dr for four years…what could have caused these results?


AskDocWeb: Well, your drug test may have come back with a false positive or a false negative, both of which could be cause for dismissal. Since you don’t actually say what your test result showed we can’t be more specific. However, it is important to find out if the urine test was confirmed with a GC/MS test or not. Although many experts recommend additional testing for confirmation upon receiving a positive urine test, that is not always done.

Primatene and Walgreens cold and flu relief?
Hi, I have a few products that I had some questions on. Primatene and Walgreens cold and flu relief. I wanted to know if I am at risk of a false positive urine screen while taking these. Any help is appreciated. Thank you.


AskDocWeb: Welcome Bradley. It appears that you do have something to be concerned about as both products have shown up in the research on false positives. Primatene contains ephedrine, which has shown up as false positives for amphetamines, meth, and ecstasy (References: 3, 11, 16, 18, 29, 32 and 57). Walgreens cold and flu relief, as well as other cold products that contain dextromethorphan have shown up as false positives for opiates (Reference: 21). Fortunately a GC/MS confirmation test can tell the difference between these products and drugs of abuse.

Ng/ml on a ua test?
I am on 240mg/day of codiene in the form of Tylenol #4’s, what would be my readings in ng/ml on a ua test…i believe there may be a discrepency in my last test.


AskDocWeb: Sorry John, there are too many variables involved to make even a wild guess. The ng/ml will vary according to your dosage, your metabolism, the time elapse between the last dose taken and the test, and your BMI.

Will benzocaine test positive as a schedule 2 drug? I have very bad teeth and use plenty of it because I cannot afford to get them fixed.


AskDocWeb: Sorry to hear about your teeth Paul. There is nothing quite like a toothache. Benzocaine has not been reported to show up on urine drug tests for drugs of abuse.

False positive for Morphine?
I was prescribed Cheritussin (gudiene sp? and Codeine) for a cough. I was also taking OTC DAYTIME cold meds, in addition to Fioricet and Norco, and my UA came back positive for Codeine AND MORPHINE! Please tell me what could cause a FALSE POSITIVE FOR MORPHINE? Thank you sooo much!


AskDocWeb: There are about 50 possible causes of a false positive for morphine listed here, many of which are used to relieve cough and colds.

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