Questions about False Positives in Drug Testing, page 190

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.

Second hand pot smoke or vitamin B2
Date: 4/2/2012
Ok so I had a hair follicle test for a preemployment drug screen. I was honestly a little nervous from the start because of my room mates activities. My room was always the hangout spot for both of my room mates. I would drink and they would smoke pot. I wasn’t interested because I work at a job that tests if you get hurt and I ask in a high risk area. Anyway I looked it up and I saw some say it’s not possible to get a false positive from second hand smoke, then others say yes you can… I failed the test for thc…

I originally thought that was the reason, but I also see hear it looks like a vitamin taker can also have this happen and I take a ton of multi vitamins for my acne. But I didn’t see any one say it was possible for hair follicle tests, only urine. I would like to know which is more likely to have caused this and if I have a leg to stand on to fight back. I don’t want to lose a 100 thousand a year job because of someone elses habits or trying to keep my acne under control. Please help. Thank you.


AskDocWeb: Hi Travis. According to an article in the Oregon Herald mega doses of vitamin B2 might cause a false positive for THC however, a confirmation test would invalidate that result. If on the other hand your test result were from second hand pot smoke because of your roommates, a confirmation test would come back positive. That sounds like a very uncomfortable choice to make. Please let us know how it turns out. Good luck.

Milk thistle
Date: 4/2/2012
I have been taking milk thistle for my liver. Took a preemployment drug test and tested positive for THC, is this posible. Have not smoked weed for over 10 years.


AskDocWeb: Milk thistle stimulates liver metabolism so that may actually help clean THC out of your system but we have never heard of it causing a false positive for anything.

False positive for Methadone?
Date: 4/2/2012
Hi, My husband goes to a pain clinic for neuropathy in his legs and feet. The last time he was there they told him his urine test came back with Methadone in it. He has never taken this type of drug. He has been taking cold and cough medicines(OTC) and OTC alergy medication. Coricidine HBP, Benadryl Allergy and Cold, Walgreens Wal-phed, Top Care Tussin DM Cough & Chest Congestion (sugar free), Aleve, Ibuprophin, and a cough medicine with codiene in it from the pharmacy. He also has Hep C from a blood transfusion many years ago. Help! Would any of these cause methadone to show up in his urine?


AskDocWeb: Antihistamines in general have been known to test positive for methadone as well as over-the-counter cold meds such as Nyquil and Vicks Formula 44M. Whenever a false positive is suspected we recommend getting a confirmation test from an independent certified laboratory. For a list of certified labs see Help beating a false positive.

Raspberry ketones and gamma oryzanol
Date: 4/3/2012
I have to give random test once a week, I was wondering if rasberry ketones and gamma oryzanol can cause a fales positive on a drug test.


AskDocWeb: Neither has been reported to cause any problems on urine tests for drugs of abuse. However, it’s always a good idea to report everything you take prior to submitting your sample. That includes prescription medications, over-the-counter meds, and supplements.

Level of amphetamines in UA
Date: 4/3/2012
My children are currently in DFACS custody. We are are randomly once a month called for a urinalysis Drug test. My husband takes zantac like it is candy. He has tested positive for amphetamines the past 3 screens. I did on the last one. We were told that the levels of amphetamines in the UA was not from him taking zantac and I had been sick and took contact cold and flu. Alka seltzer


AskDocWeb: Most urine tests on give a yes or no answer to the question about the presence of drugs of abuse. In order to measure a concentration level they usually need to do confirmation testing, which rules out false positives.

My Friend Needs Help
Date: 4/3/2012
My friend recently went in for a random drug screening at work. I strongly beleive that she does not do drugs, and would do nothing that would result in her losing her job or a chance at losing her son, however when the results came back she was supposeldy positive. The only thing she claims to have had are energy drinks, and then the urine sat over the weekend before being sent in. Is it possible that she can prove that she wasnt on drugs? and get her job back?


AskDocWeb: To our knowledge the only way to prove that the original sample did not contain the metabolites for drugs of abuse is to do a confirmation test on that original sample, preferably by an independent laboratory that is certified for federal drug testing.

Over the counter medication
Date: 4/3/2012
Can one of these over the counter medication show up on in a urine drug test: Advil, Tums, Orajel. Thank You,


AskDocWeb: The only one of those that might be a problem with drug testing is Advil (Ibuprofen). Several sources say that might cause a false positive for marijuana.

How could this happen?
Date: 4/3/2012
I have a question. I had to take a urine and hair follicle drug tests a couple weeks ago for a new job. I have never in my life done any illegal drugs. My urine test came back clean. My hair follicle test came back positive with traces of cocaine in it. I would like to know, how could this happen? How can a person have a positive test when they have never done any illegal drugs much less cocaine? Thank you,


AskDocWeb: While it sounds unlikely to have that combination of drug test results, it might be possible if the cocaine contaminated your hair topically. Have you been in contact with anyone that uses cocaine? Other than that the only possibility that we can think of is some kind of lab error, which is even less likely but still possible.

Crystal Meth?
Date: 4/3/2012
Hi. I see a Pain Management doctor and am give Oxycodone for severe pain. Today I went in for my regular visit and they do a drug urine test. I tested positive for Crystal Meth! I don’t even know what Crystal Meth looks like! The only things I take are the oxycodone, zantac and occasionally Atarax which was given to me for severe nausea. I also use on Electronic Cig. I can’t think of a thing that would cause this. The only thing different from the previous visit is that I saw a dentist yesterday to have a cavity filled and my mouth was numbed. The doctor is sending my urine sample off to have GC/MS testing done. Again, I was shocked. I’ve never, ever touched Crystal Meth. What on earth could have caused it to show up in my urine???


AskDocWeb: According to two of the companies that make the drug testing kits Zantac may cause a urine test to show positive for meth. The good news is that the GC/MS confirmation test will eliminate that kind of false positive.

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