Questions about False Positives in Drug Testing, page 243

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.

Tested positive for phenobarbitol
Tested positive for phenobarbitol, I have never taken anything I can think of that contains it. I did a colon cleanse with my chiropractor the week before. I’ve never drank smoked or done drugs in my life. Now I have to go to court for something I can’t even explain why I’m positive. I don’t do anything. Please help.


AskDocWeb: As we understand it, the urine drug tests are considered presumptive evidence. That means that when your test results are positive, you are considered guilty until proven innocent. In order to prove your innocence the original sample has to be run through a confirmation test such as a GC/MS, preferably by an independent certified laboratory.

False reading sucks
I take hydrocodone 7.5-750 twice daily loratadine 10 mg simvastin 10 mg metformin hcl 850 amoxicillin500 mg levitra zolipidem tartrate 10 mg cephalexin 500 omeprazole 20 alprazolam 2mg paroxetine 30 lamotrigine 200 amlodipine 5 mg linsinopril 20-25 mg baclofen 10 mg and ducosate sodium 100 mg also wad on endocet 7.5 a week or so ago peed in a cup today doc said I gotta wait three weeks for pain meds because they had to send urine to lab said something showed up I swear this is all I take other than insulin and don’t smoke pot. Can any off these or combos give me dome kinda false reading? It sucks cause ill be out of my pain meds next week.


AskDocWeb: Two of your medications are known to have caused false positives on urine drug tests for drugs of abuse. Several sources say that Amoxicillin may test false positive for cocaine (References: 13, 16, 18, 20, 21, 26, and 29). Omeprazole and other PPIs may test positive for THC (Reference: 37). A confirmation test at a lab will be able to sort this out but you are right, having to go without your meds because of false positives is unpleasant if not dangerous. You can thank the failed “War on Drugs” for treating people with certain medical problems as if they are criminals.

Buffer room
I submitted a response regarding a false positive for benzodiazapines due to what I believe to be benadryl. Id like to thank you for the info/help. It occured to me while reading the answer that there is a certain amount of “buffer room” (as far as measurements/levels) before the testing facility will quantify the test as having a “positive” result. Why would they need to do this? Is it due to the possibility of human error, or does the human body already have pre-existing chemicals that medications might mimic? Thanks again for all the help this service provides for so many people.


AskDocWeb: Any activity that humans do involves the possibility of human error. Also there are a couple of medical conditions that are known to affect the accuracy of urine drug tests, kidney disease/dysfunction and diabetes.

False positive for MDA
I have a question, i got a false positive for MDA and the only medications was taking at the time were seroquil 300mg cloanidine twice a day..zoloft lamitcal 100mg metformin twice a day.. i was neg for everything else even mdma… i dont understand how i could come up positive for MDA….they are trying to charge me with a dui… but i know i didnt take any mda.. can you please explain this to me?


AskDocWeb: Hi Cassie. None of the medications you list would explain a false positive for MDA. You might have to spend some money to ask a Lawyer but it sounds like you will need to get a confirmation test on that original sample. That is, if you really think that it is a false positive.

MDA is methylenedioxyamphetamine or more commonly known as the love drug.

Sudafed or Zyrtec?
Can sudafed or Zyrtec show on a UA? I was prescribed last week for allergies and have conditional job offer with a hospital pending the UA. Did not think if this until this afternoon. Thanks.


AskDocWeb: There are several sources that say Sudafed may show up as a false positive for amphetamines, meth and/or ecstasy (References: 3, 11, 16, 18, 20, 26, and 29). Zyrtec-D may also show up on urine drug tests because it contains pseudoephedrine. That may cause a false positive for amphetamines (References: 3, 11, 18, and 21).

Tested positive for opiates
I am an opiate addict who has been in recovery for 3 years. I have been clean and proudly sober of ANY opiate use since June 19, 2010; a little over 2 years ago now, since entering a methadone program. I recently earned the highest Phase in the program – Phase 7 – with 4 weeks of take outs. Two weeks ago, I proudly gave my random urine sample. And have tested clean for more than one year.

I had a stomach procedure, where I had to be sedated, making ABSOLUTELY SURE I was not given any narcotic or benzodiaopine to relax me. The anethestist used something called Propofol (?) and now I’ve tested positive for opiates. I don’t understand at all. I was given some other stuff in my IV just before the procedure – but was told up & down, it contained no narcotics.

I’m scared. I’ve worked SO hard, and have earned my takeouts. I have no issue taking accountability for my behavior, or admitting when/if I’ve used. But I haven’t used in over 2 years!!! Please help. I don’t want to lose where I’m at — since I drive 100+ miles to the Methadone clinic. What could I have possibly done to cause a false positive??


AskDocWeb: Hi Amy, welcome. Propofol is a hypnotic agent and would not show up on a drug test for drugs of abuse so you can rule that out. You might contact the hospital to find out exactly what that “other stuff” was that they put in your IV. When you find out, check to see if it is on this list. In any case, we would go for a confirmation test to eliminate false positives.

Quinine water?
Would quinine water give a person a false positive drug screen?


AskDocWeb: The quinine in quinine water, also called tonic water may show up as a positive for opiates (References: 26, 29 and 32).

Chances of messed up drug test?
I had a piss test come up positive for buprenorphine and the next one came up dilluted, and i havent taken a suboxone or anything like it.. i was on meds for my bladder infection and i take alot of vitamins. I know the dilluted one was prob cause the uti but the positive one i am stumped..Help. It gets sent to a lab, is there anyway they messed mine up or it got switched?


AskDocWeb: With the chain of custody employed with most drug testing, the chances of that are very remote but mistakes do sometimes occur. When it happens it is usually because the physician doesn’t understand the legal chain of custody procedures. Unless otherwise instructed, they will usually follow clinical laboratory standards, which do not stand up to a challenge by a knowledgeable attorney.

The chain of custody is a monitoring and accountability process to prevent tampering with the sample and the results. There are legal standards that regulate the handling, analysis, and collection of samples if they are intended to be admissible in a court of law. The chain of custody begins with collection of the urine, and continues through the final reporting of test results to clients. It involves sealing of sample containers, transport and control of samples, receipt of samples by the laboratory, and supervision of lab tests under strict discipline throughout the process. Authorized signatures are required at each step. If there are weak links anywhere in the chain, the results can be effectively challenged in court of law.

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