Feedback on False Positives from Drug Testing, page 29

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: Lidocaine?
Date: 12/21/2007
I cut a finger at work, and they tested me for drugs, I got positive with cocaine, and I never used it. Before I gave the sample, the doctor put me lidocaine, then 3 stitches and a tetanus vaccine and after 45 minutes later, he tested me for drugs. Does lidocaine can make a false positive? Thank you.


AskDocWeb: We have not yet found a reference for lidocaine that would admit the possibility of a false positive.

Subj: Tested positive for THC
Date: 12/22/2007
I recently tested positive for THC. The only thing I take is Ibuprofen. I am in a program that tests my urine about 1 time every 10 days. If I cannot prove that I am negative I could lose my license. Is there a test that can prove that the test was positive because of the Ibuprofen instead of Marijuana?


AskDocWeb: Yes, that test is called a Gas Chromatograph/Mass Spectrometer or GC/MS confirmation test.

Subj: Adderall
Date: 12/25/2007
I’m in the army and I take Adderall for ADHD. Anyway I pop hot every time but this time they said I was taking escasty and there is no way, I don’t use that stuff. Is it possible that they made a mistake on testing?


AskDocWeb: When human beings do things there is always the possibility that someone can make a mistake. A GC/MS confirmation test can clear that up.

Subj: Tested positive for THC
Date: 12/26/2007
My daughter was given the EMIT test at the county jail and tested positive for THC. Her levels were low, she had taken 1 tylenol and 1 ibuprophen 2 days before, can this cause a false positive?


AskDocWeb: That is a pretty low dose so probably not. From what we have read the dosage has to be much higher.

Subj: Question
Date: 12/27/2007
If I am taking Phentermine and am given an “on-site” test for amphetamines that comes back positive, will a confirmation test show that I am not, in fact, taking amphetamines?


AskDocWeb: Yes, that is the reason to get a GC/MS confirmation test.

Subj: False positive information
Date: 12/28/2007
It is very important that you clarify your false positive information. What you are referring to is false positives on screening tests not confirmation tests. Also much of the info that you have on your site dates back to the 70’s. (ibuprofen causing false positives) What you are referring to is a specific screening test (brand) that was used in the 70’s that would screen positive. This type of screen is no longer used and the current screening tests will not screen positive for marijuana. It is very important that you make it clear on your site that if a gc/ms (gas chromatography and mass spectrometry) test is done, even if something falsely screens positive, the confirmation tests will rule out any false positives and can differentiate promethazine from thc. There are no false positives on confirmation testing. People are trying to do anything they can to try to keep from taking responsibility and blame someone or something else for their positive results. You are doing quite a disservice to individuals and companies that are involved in drug testing by intentionally omitting this information.


AskDocWeb: You can say that there are no false positives on confirmation tests but that isn’t what we are talking about here. We are discussing false positives on the initial urine drug tests. According to the Journal of Family Practice, October 2006, ibuprofen caused false positives for both Barbiturates and cannabis at the rate of 0.4%. This means that for every 10,000 people who take ibuprofen and get an employment drug test, 40 people could loose their jobs. We hope that you never find yourself in that small percentage because trying to contest such a result is almost impossible. Even the U.S. Justice Department admits that the EMIT can have false positive rates up to 2.5 percent.

Subj: Dextromethorophan
Date: 1/2/2008
I am in a drug rehab program and will be tested tomorrow on 1/2/08. I took a Nyquil on 1/1/08 because I have a cold and it contains Dextromethorophan. The page states that Dextromethorophan may cause a false negative, but for what type of drug? Do you think I will be able to pass?


AskDocWeb: The list of causes for False Positives has been updated to include all current information.

Subj: Equate Sinus and Congestion
Date: 1/2/2008
Can Equate Sinus and Congestion (which states on the box that it has the same ingredients as Tylenol Sinus) cause a false positive for cocaine? I recently had this happen to me where I tested positive for something I do not do.


AskDocWeb: Typically if two products have the same ingredients then they both produce the same results.

Subj: Reference for amoxicillin
Date: 1/2/2008
One of my patients has tested positive in a hair test for cocaine. I performed a root canal on her 6 months ago. Could this still be present in a hair specimen? She was given heavy bolus doses of amoxicillin prior to appointments due to a recent hip replacement. If this could be a factor in her test results could I trouble you for a reference in a refereed scientific journal which states this as a fact? I do not want her to lose her job. Thanks,

Dr. Rakich

AskDocWeb: The references we have for amoxicillin are here. See numbers 13, 16, 18, 20, 21, 26, and 29.

Subj: Supplement called Torque
Date: 1/3/2008
My brother-n-law got an oral swab test done and came up positive for metabolites but negative for cocaine. He had been recently been using a supplement called Torque and had been to the dentist (he had some drilling done on his gums) a week prior to his drug test. Could any of this have any affect on why metabolites might’ve came back positive?


AskDocWeb: There have no reports about Torque howevere, a trip to the dentist office may produce a positive for opiates if he received Novocain. (Reference 52)

Subj: Gasoline or matches?
Date: 1/4/2008
Would or could gasoline or matches cause you to test positive for meth? Say you had gas on your hand and touched the inside of the container you were testing in?


AskDocWeb: We have never heard of such a thing happening and have no idea what kind of results that would cause.

Subj: Positive urine test
Date: 1/4/2008
Hi, I had to take a urine test at my doctors and my results came back with a positive PCP in it. I haven’t done any drugs, matter of fact I’ve been in N.A. for about four mos. and have been clean for 94 days now! What can it be? I take many different medications, but my doctor seems to think I’m doing drugs. Please Help! Thanks,


AskDocWeb: You might want to go over all the medications you take with this list to see which one could be the culprit.

Subj: False positive list
Date: 1/4/2008
Is there any way that you can substantiate your false positive list? I would like to use the list in a hearing I will be attending in the very near future.


AskDocWeb: We have added references here.

Subj: Neurontin
Date: 1/4/2008
I tested positive today for benz, and I am taking neurontin, is this possible? Please get back to me as soon as possible


AskDocWeb: Neurontin (gabapentin) is used for the management of postherpetic neuralgia in adults. It has not been reported to cause false positives in drug tests.

Subj: Ambien CR
Date: 1/5/2008
I was just wondering if ambien CR or any kind of over the counter sleep aid will come back as a positive when taking a drug test?


AskDocWeb: Ambien CR has not been reported to cause false positives on drug tests.

Subj: Meloxicam
Date: 1/5/2008
Will meloxicam show a false positive for marijuana?


AskDocWeb: We have had no reports of that happening.

Subj: Ativan?
Date: 1/5/2008
Benzo- In a random urine screening as an outpatient being treated for PTSD/alcoholism, I tested 1160 for benzodiazapenes. I do not, nor have I ever taken drugs, even avoiding prescriptions at all costs (e.g., I lost weight so as to get off blood pressure meds, which worked.) I have been refusing psyche meds, opting for an intensive vitamin regimen instead. On Dec 9, I was hospitalized for drinking heavily due to flashbacks from the PTSD, at the same hospital where I am attending the IOP program. I think (not sure) I might have had a day or two of ativan? During the detox period- I’m looking into that. Is it possible for that much to still be in my system a month later? My liver functions were returning to close to normal upon discharge from inpatient Dec 15th. I should also mention that this also happened about 6 months ago after a hospitalization for the same problem. I know it sounds unusual to say I have a drinking problem sometimes, but I swear I do not take drugs and have not been on anything since Dec 15- discharge, including alcohol. I did agree to another test, because of course I want to validate that the lab did not make a mistake, and should have those results by Monday. Can you give me any advice or suggestions?


AskDocWeb: Ativan is a benzodiazepine but it should have been out of your system in just a few days. The half life of Ativan (lorazepam) is only 10 – 20 hours.

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