False Positives on Drug Tests, page 150

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.

Subj: Positive for marijuana
Date: 9/21/2011
My husband took a DOT test for a job we desperately needed, his test came back as positive for marijuana .08? He does NOT smoke pot, however he does have friends that occasionally do. He is not around that often, however could this have caused it? I use a cream that has Marijuana in it for pain, he has used this on his back, could this have caused this? We are so preplexed, and this is so unfair! Please help!


AskDocWeb: Let’s make sure we understand this correctly. Point 1. Is he really using a product that contains marijuana when his job depends on a clean drug test? That sounds like he doesn’t really want the job. Point 2. Does he know that others have lost their jobs because of inhaling secondhand marijuana smoke?

Subj: Clenbuterol or ketotifen?
Date: 9/21/2011
They aren’t listed on your site but i want to double check, does clenbuterol or ketotifen show up in drug test?


AskDocWeb: If they are testing specifically for Clenbuterol it will show up for 4-6 days after use. That is usually limited to international competitions such as the Olympics or the Tour de France. It is listed by Wada as an anabolic agent and is prohibited for use by athletes at all times in and out of competition. However, it will not make you show positive for any drugs of abuse on a urine test for employment or probation. The US military doesn’t test for it.

We found plenty of false positive results involving ketotifen but they were all related to skin testing for allergies and other disorders, none for drugs of abuse. Of course the absence of evidence is not proof but we were unable to find a single case where either drug caused a false positive on a urine drug screen for drugs of abuse.

Subj: I was terminated from my job
Date: 9/22/2011
I have a very interesting, but baffling case. On April 30th of this year, I took family member’s (with permission of course) valium- 10mgs, because I was out of my prescription Alprazolam. 18 days later I urine drug tested by my employer. The urine drug screen results showed positive for oxazepam. I was terminated from my job and have had to deal with my state board (nursing) recovering professionals program.

Since then I have had questioned whether the Xanax could have caused a false positive for oxazepam. Hair follicle tests have come back negative for both xanax and oxazepam (done within a month of taking the valium). I am on Ibuprofen (Rx strenth), Flexeril, Lisinopril, Cymbalta, and pravastatin. The MROs that I have dealt with state that 18 days is too long for the valium to have stayed in my system. Could the Xanax caused a false positive for oxazepam or could a combination of any of these meds have caused this result?


AskDocWeb: The first question to ask when your job depends on a urine drug test is: “Are the test results confirmed by a GC/MS confirmation test?” Until that happens, there is still a chance of keeping your job or getting it back.

Both Xanax (alprazolam) and Oxazepam are benzodiazepines however, they are in different groups within that classification. Oxazepam is an active metabolite of diazepam, which is a metabolite of chlordiazepoxide. Xanax is metabolized to 4-hydroxy-alprazolam (90%) (an inactive benzophenone) and alpha-hydroxy-alprazolam (10%).

Although there are a couple of anecdotal reports of Xanax showing up as oxazepam we have not been able to document that as a legitimate possibility.

Subj: Can kissing and sexual contact make you test positive?
Date: 9/23/2011
I recently tested pos for thc. I do not smoke pot. I am not around any poy smoke. My girlfriend smokes pot and was wondering if kissing and sexual contact can make you test for a false positive. Any info would be great. I could go back to jail because of this. thank u.


AskDocWeb: Absorbing enough THC through physical contact to show up on a drug test seems highly unlikely. We have heard of that happening with cocaine but not with marijuana.

Subj: False positive for PCP
Date: 9/24/2011
My husband took 2 drug test at the probation office which came up positive for PCP then the probation officer took him to the hospital where he was tested again and the test were negative. Two weeks prior to that he had a drug test for a job and those test were sent to a lab and came back negative. I gave him some Nyquil before his test at the probation office could the dextromethorphan in the nyquil cause a false positive?


AskDocWeb: Nyquil has been documented to sometimes show up as a false positive for amphetamines, heroin, opiates, morphine, meth, ecstasy, and methadone but not for PCP. The only substances that have been reported to cause a false positive for PCP are Diazepam, Diphenhydramine (Benadryl), Doxylamine, Effexor Tablets (venlafaxine hydrochloride), Ketamine, Lamotrigine (Lamictal), and Tylenol Simply Sleeps (Diphenhydramine).

Subj: Hair follicle test
Date: 9/25/2011
I am currently taking wellbutrin and a couple weeks ago was on celexa. What is the chances that it will come up on my hair follicle test as a false possitive and what would it come up as on a hair follicle test.


AskDocWeb: Sorry Chadd, we are still collecting data about hair testing so questions about hair testing are being added to a list for now. Hopefully we will be able to open a forum for that later this year.

Subj: Doctor decided to cut off his pain meds
Date: 9/25/2011
My husband is on hydracodone for his back pain, his doctor recently had him randomly tested to make sure that he was taking the appropriate amounts. Well, he is a welder, so he drinks lots and lots of water through the day. The morning of his test he drank some milk so he could take his blood pressure meds, he wasn’t sure if he was still supposed to take the meds or not. So that day, he tested negative for any drugs in his system, and his doctor decided to cut him off of his pain meds. Now she won’t return his calls and are afraid of getting a referral for a pain management doctor without looking like he is a drug seeker. Can you give us some advise please.


AskDocWeb: Whether your drug test showed false positive or false negative, there are a number of things you can do to protest the results. Here’s a description of a protest campaign that others have used. Feel free to use any part or all of it.

The first thing is to write a letter of protest stating that you believe the test was inaccurate. It doesn’t have to be elaborate or contain a lot of detail. Just a statement that “the test was inaccurate and damaging” is sufficient. In your letter, request the following:

  1. Complete identification of the particular test that was used, Brand name
  2. CLIA and/or FDA certification number for the test
  3. The laboratory certification number for each agency or organization involved in the testing process
  4. The chain of custody form (COC). Each person that handled your sample had to sign the chain of custody form. The COC is a very important document. If it is not maintained the test is without value and your test results are invalid. The COC should allow you to determine if unqualified individuals handled your test.

You have the right to know the brand name and identification of any test that was performed on you.

Now send a copy of that protest letter to every person, agency, and organization involved in the testing process. If you already know the name of the testing agencies (ex. Physician, laboratory, etc) you can check their certification by going to LABORATORY LOOKUP. That page will allow you to lookup any laboratory by name or their 10 digit ID number.

Once you have identified the laboratory(ies) involved, you can send a copy of your complaint to the CLIA Regional Office for your region. To find the appropriate address for your area, click here.

You can also send a copy of your complaint to the state agency that is responsible for laboratory regulation. The responsible agency for your state can be found on this page.

Some tests do not have to be certified by CLIA but still must have an FDA waiver. These are mostly tests that are sold for home/personal use. You can then check the test used against the Federal Drug Administration list to see if it is exempted and for what uses at Tests Waived by the FDA.

Note: The FDA exempts drug tests for specific reasons but it is not a blanket exemption. Most of the waivers are issued for tests that are used only in the home. Some businesses have been reported to order home drug tests and use them for in-house employee drug testing. That is not allowed. So look up your specific test and read the FDA waiver restrictions for it.

Last but not least, you can check to see if any past legal action has been taken against a certified laboratory at the Laboratory Registry)

Now you have the information needed to file your complaint with other accrediting agencies. CLIA sometimes delegates accreditation to one of 6 other approved organizations. If the lab may be certified by one of these other agencies you would file your complaint with that organization. Those 6 agencies are listed here:


8101 Glenbrook Road

Bethesda, Maryland 20814-2749

Government Relations

(301) 907-6977

American Osteopathic Association

142 East Ontario Street

Chicago, Illinois 60611

(312) 202-8070

American Society for Histocompatibility and Immunogenetics

15000 Commerce Parkway, Suite C

Mt. Laurel, New Jersey 08054

(856) 642-4415

College of American Pathologists

325 Waukegan Road

Northfield, Illinois 60093-2750



9881 Broken Land Parkway, Suite 200

Columbia, Maryland 21046-1195

(410) 381-6581

Joint Commission

One Renaissance Boulevard

Oakbrook Terrace, Illinois 60181

(630) 792-5000

Even if the lab is certified by another approved regulatory body, you can send an informational copy to the CLIA Regional Office and the other agencies listed above.

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