Feedback on False Positives from Drug Testing, page 102

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: Tested positive for cocaine
Date: 9/14/2010
I have googled the internet until my fingers are bleeding. my client tested positive for cocaine (150 screen, 100 confirm, by Pharmatech). He says he did not do cocaine. The collectors were very sloppy but that does not explain how the benxylocognine showed up in his urine, unless we go the conspiracy/plant theory. HELP.

AskDocWeb: Benzoylecgonine is one of several metabolites of cocaine. It is formed from the hydrolysis of cocaine and is a very specific marker for that drug. However, there are at least two other ways that cocaine can get into a person’s system so if benzoylecgonine is found in the urine, that by itself is not evidence of illicit cocaine use. There are cocaine-containing anesthetics that are used by ear, nose, and throat specialists. Use of these anesthetics may produce a positive drug test for up to 48 hours after use. There is also a possibility of getting it from mate de coca, a coca leaf tea. Although the cocaine is supposed to be removed from the imported tea, some may still contain small amounts of cocaine.

Subj: Atenolol and trazadone?
Date: 9/15/2010
Would atenolol and trazadone show up in a court ordered drug screen?

AskDocWeb: According to, trazadone is a common misspelling of Trazodone. The New York State Office of Alcoholism and Substance Abuse Services says that it has shown up as a false positive on urine drug tests. Trazodone (also sold as Desyrel and Oleptro) is a serotonin modulator used to treat depression. It works by increasing the amount of serotonin, a natural substance in the brain that helps maintain mental balance.

Atenolol is a beta blocker, which is used alone or in combination with other medications to treat high blood pressure. It is also used to prevent angina (chest pain) and improve the chances of survival after a heart attack. It has not shown up in our research on false positives.

Subj: Kelex?
Date: 9/15/2010
Well on August 25 2010,I had a on the job accident, I was given a drug test and it came back positive and they gave me 500mg of kelex before they gave me a drug test. Could that mess up my drug test?

AskDocWeb: We are going to make an assumption here (grin) that kelex is a misspelling of Keflex and that your post has nothing to do with the tolerance limit of zinc deposits to organic extractants or hydrometallurgy. Keflex (Cephalexin) is an antibiotic used to treat bacterial infections in the bone, ear, skin, and urinary tract. While some antibiotics have shown up as false positives for heroin or cocaine (References 13, 18, and 20), Keflex has not been identified as one of them.

Subj: Drug test at work
Date: 9/16/2010
My doctor has been switching my meds around and I know I’m due for a drug test at work. 3 days ago I stopped taking syrquel and now I’m on Zyprexa. Will these cause any positive results for meth, amphetomines or cocaine?

AskDocWeb: According to the information we have, you should be okay. However, if you do get a false positive, remember that a confirmation test is required to prove it.

Subj: Positive result for opiates
Date: 9/16/2010
I recently had a possitive result for opiates on a random urinallysis the ONLY prescriptions I take r suboxone, trasadone, valporiacid, and oxcarbazepine cld any of these cause a false possitive?

AskDocWeb: The only one of those that has been reported to cause a problem is the trazadone.

Subj: Naproxen?
Date: 9/16/2010
I’m taking a pre-employment drug test at 11 a.m. tomorrow, and just found out that naproxen can cause a false positive. I take 500 mg of naproxen for my arthritis, about once a month. I just happened to take one about 10 last night. Will this small amount, about 36 hours later, have any effect?

AskDocWeb: Naproxen has a half-life of about 12 hours so it could take up to 60 hours to completely clear your system. There is a very small but still real chance that it could show up on a drug test.

Subj: Terrified of drug test
Date: 9/17/2010
I’m currently on Probation and i got a notice yesterday that I have to report Monday. I have had a cold for a week now and the only thing i can take is Robitussin DM and Sudafed and Tylenol. But I only take Tylenol for my headaches because I’m pregnant with my 3rd child. I was given a list of medications i can take that will not harm my unborn child and Sudafed & Robitussin DM are both on there. I’m terrified that I’m going to end up with a false positive and be violated and I do not have the money to have that sent to the lab if it comes back positive. I have 3 years of probation and I was put on it in 2009. It’s been a year so I still have 2 years left and i so afraid that I’m going to jail and lose my children because of a false positive. I have in the past used drugs but that been 5 years ago and since I have became a mother I have left that life behind and I passed every drug test since 2009 but now as i said I’m terrified that I’m going to jail and i will lose my children and we do not have that money to bond me out if that’s happens. What should i do? I been there once for the charge that got me the probation and i never want to go back!

AskDocWeb: Learning more about what you are afraid of is a good way to help cope with that fear. Now that you know that urine tests are not perfect, and that they have an error rate, you don’t have to accept the results of a false positive. You may even be able to avoid one by choosing alternatives to those things that have caused problems for others.

Subj: Motrin 800
Date: 9/17/2010
i have a script for motrin 800. and i took 2 in the morning and one at bedtime. i have to drop in the morning. and my script is expired. Can i get in trouble for taking it?

AskDocWeb: Motrin (ibuprofen, also sold as Advil, Nuprin, and Medipren) has shown up as a false positive for THC. Whether or not you can get in trouble for using it depend on a number of things. How long ago did the prescription expire?

Subj: Tested positive for cocaine!
Date: 9/18/2010
I had minor surgery and the Dr. used 12mg’s or units of lidocaine to numb my face and when I had a hair drug test done it tested positive for cocaine!!! The units were so high that it showed up that I was a daily user and I had not ever touched the stuff. Now Im reading things about how hair test dont test for the metabolites and this is what can cause the false positive for cocaine. IDK all I do know is that I had not touched cocaine and cant believe in this day that there can be such a problem with hair tests. Another Dr. I spoke to said that hair testing can detect so many things that can be confused to cause false positives that he disagree’s with ever using a hair test to verify someone using drugs of any kind. He feels a weekly or daily urine test is more accurate. The lab test not an at home testing.


Subj: Cha’ de bugre
Date: 9/19/2010
Will cha de bugre show positive for amphetamines

AskDocWeb: Cha’ de bugre is a very popular beverage in Brazil. It is said to have both weight loss and appetite reducing effects. It has not been reported to cause any problems with urine drug testing.

Subj: Cannabis family?
Date: 9/20/2010
I showed up positive for THC and I am taking Trazodone and I found out that it is a tryacyclic drug which is part of the cannibas family…


Subj: Tested positive for POT
Date: 9/21/2010
Had to take a drug test last week and medical review officer says I tested positive for POT. I take Protonix twice a day and also about 6 to 8 ibuprofen for headaches. I drive a RTD bus. I haven’t smoked pot and according to my DR. and medical review officer they can do a more extensive test ruling out my meds. I still insist I haven’t smoked pot. How can I prove I haven’t? Can I win this case?

AskDocWeb: The fact that they “can” do a more extensive test to rule out your meds is a good thing. Now, have they done that? If not then that would seem to be the next step. If a GC/MS confirmation test can’t confirm the presence of THC, that shows that the results of the first test are a false positive.

Subj: Synthetic marijuana (K-9)
Date: 9/21/2010
With the new use of synthetic marijuana (K-9), will it test positive for PCP on a drug screen?

AskDocWeb: We haven’t found anything to support that possibility. However, there are reports of people wetting or lacing synthetic marijuana with PCP.

Subj: Vivitrol (naltrexone) injections?
Date: 9/21/2010
I work for a substance abuse counselling facility. One of our counselors is asking if its possible for the new Vivitrol (naltrexone) injections to cause a false positive for PCP. Do you have any information regarding this?

AskDocWeb: No, and research didn’t turn up any accounts of such a false positive.

Subj: No chain of custody?
Date: 9/21/2010
My girlfriend is currently in residential treatment because of CPS involvment. She has been clean for 3.5 months. The rehab has her on wellbutrin and trazadone. At a UA 2 says ago she tested positive for marijuana and benzoes. The rehab also has no chain of custody or allows client to witness sealing of sample. Could this be a false positive?

AskDocWeb: That is possible. Not having a chain of custody means that their process is probably vulnerable to several legal land mines. Do they have a license to operate that rehab center?

Subj: Dextromethorphan?
Date: 9/22/2010
I had an Army UA this morning and had taken Nyquil late last night/this morning to fall asleep. I hear that the dextromethorphan (sp?) in Nyquil can test false positive for PCP. First, is this true? And second, can they confirm/deny with a GC/MS? I know they use it, but I don’t know if it would still test positive for similar metabolites.

AskDocWeb: Dextromethorphan has shown up as heroin, opiates, and morphine in urine tests but NOT PCP. The GC/MS test is accurate enough to tell the difference between these false positives and the real thing, which is why it is used.

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