Feedback on False Positives from Drug Testing, page 47

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 oxycodone
Date: 10/8/2008
I have been going to a pain clinic for the past 6 years and taking the same medicine for the past 3 years. I am currently taking MSContin, Soma, and Klonopin. Over the counter I use Zicam with Menthol, Afrin with Menthol, Ibuprophen and aspirin occassionally. I have severe kidney disease with some damage done to nerves from surgeries gone wrong. About a year ago my pain clinic starting doing urine tests. I have been tested 5 times now, and 4 out of the 5 have tested positive for Oxycodone. I do not, have not, nor will I ever take anything NOT prescribed to me. The meds I take make me able to work and support my family (I’m a single mother who does not receive child support). Without my meds I can not sit for 5 minutes (which in my work I sit at a desk). I do not believe on living off the Government, but would have to quit my job without these meds. On Friday I had another urine(the 5th test) which came out positive for oxycodone. I requested a blood test for drugs. Since I am NOT using oxycodone of any shape or form, will the blood test prove it? And, why are my urine tests coming up positive for something I’m not taking? Thank you so much. I look forward to hearing from you.


AskDocWeb: The combination of the morphine you are taking (MS Contin) with the benzodiazepines in Klonopin could cause problems on most urine tests. Below are some of the possible causes.

  • Afrin – false positive for Ecstasy (MDMA), Meth (Ref: 3, 11, 16, 18)
  • Aspirin with Codeine (Ref: 18)
  • Ifenoprofen – false positive for THC, Marijuana (Ref: 3, 13, 18, 21, 26)
  • Klonopin contains benzodiazepines (Ref: 18)
  • MS Contin Tablets contains morphine (Ref: 18)
  • Soma with Codeine (Ref: 18)

To check the reference numbers click here.

Subj: Red bull?
Date: 10/9/2008
I took a drug screen and they said there were traces of benzos. I have been clean for 9 months. Can red bull give me a false positive?


AskDocWeb: Several people have reported testing positive after consuming energy drinks, enough that it makes us wonder if there might be a problem although there is no evidence yet.

Subj: Positive for THC?
Date: 10/10/2008
What could cause a false positive drug test for marijuana? I am being tested on a regular basis and had a test come back positive for THC (THC level 256, creatine/THC ratio of 111), I have not been using nor have I been around anyone who has. Also how long would it take at these levels for a test to come back clean?


AskDocWeb: Marijuana takes (CENCORED) days to leave the body of occasional users. For frequent users, it stays in the body for (CENCORED) weeks. Here is the list of things that may show up as THC.

Subj: Positive for methamphedamine?
Date: 10/10/2008
Will taking any product that contains pseudoephedrine, such as Mucenex, Sudefed etc cause you to drop positive for methamphedamine?


AskDocWeb: According to our sources (References 3, 11, 18, 21, and 30), products containing pseudoephedrine may be detected as amphetamines or speed. They make no mention of methamphetamines.

Subj: False positives for alcohol?
Date: 10/10/2008
I need information on what causes a false positive reading for alcohol in a urine test. Please will you email to me by Oct. 13th 2008 custody depending on all the information I can gather. Thank you,


AskDocWeb: Sorry Caryn, we don’t have any data on false positives for alcohol.

Subj: Hair test
Date: 10/12/2008
I was given a hair drug test in Oct. On July 25 I was given a epidural when I had my son. The hair test I took came back postive for cocaine. I look up the meds given in a epidural they are procaine, lidocaine and tetracaine. I have never done any drugs. So could the meds in the epidural caused the postive for cocaine. If so can you please give me as such information you can? Thank you.


AskDocWeb: Sorry Sheila, the list we compiled is for false positives on urine tests and doesn’t apply to hair tests.

Subj: Ephedrine
Date: 10/14/2008
My husband has recently admitted to cocaine use. He hasn’t used in 3 weeks. One of the conditions for him being able to stay in our home was that he did a Random drug test any time I chose. I work in a Doctors office and we do random screen periodically on our chronic pain med patients. I took a test home and made him pee in a cup. The Cocaine was negative but he was positive for meth. My question is will Ephedrine give a false positive for meth. He denies meth use but he does take the ephedrine daily.


AskDocWeb: There are several sources that say Ephedrine may show up as a false positive for Meth, see references 2, 3, 11, 16, 18, 29, 30, 32.

Subj: Positive for marijuana
Date: 10/14/2008
My son took a urine screen and it came back positive for marijuana. He swears he hasnt touched it in several months. The results scored a 42. Could there be a chance the results were a false positive. He daily takes Singular 10 mg, Alegra 180 and usually 200- 400 mg of Ibuprophen each night. For 1 1/2 weeks prior to the screening he was also taking Albuterol in a nebulizer 2 – 3 times a day. In addition, 1 1/2 days before the screening he was in a accident and prescribed 800 mg motrin for a head injury at the hospital to take every 8 hours. He took two on Thursday and two on Friday…his screening was done on Saturday morning. Any info is greatly appreciated.


AskDocWeb: While we aren’t sure about all urine tests, most of them have an error rate of some percent where they show a false positive. A positive result on a urine test is an indication of possible drug use but it should (in our opinion) be confirmed by a GC/MS confirmation test.

Subj: Lisinopril HCTZ?
Date: 10/14/2008
Would Lisinopril HCTZ cause a false positive for benzos on a drug screen?


AskDocWeb: Lisinopril HCTZ has not been reported to show up as a false positive for anything. Lisinopril (Prinivil) is used for the treatment of hypertension.

Subj: Viagra?
Date: 10/15/2008
Just wanted to know if viagra can show a false positive on a drug screen?


AskDocWeb: There is no problem with Viagra on drug screens so go ahead and enjoy it.

Subj: UA drug screens
Date: 10/15/2008
I work on a Crisis Unit and we are required to do UA drug screens and have ran into people claiming false poitives. I was woundering if you could provide me a list so when people claim false positive we can look up what they are telling us they take and see if that is the cause. Thanks for any help you can provide.


AskDocWeb: Yes, the list is located here. Please note that this is an ongoing project and items may be added or removed as new information becomes available.

Subj: Tested positive for cocaine
Date: 10/15/2008
I tested positive for cocaine, but I don’t use. I currently take norvasc (5 mg) a day for high blood pressure and phendimetrazine blue (35 mg)as an appetitite supressent. I think my husband is using cocaine, can I test positive from any of my prescriptions or can I test positive from his semen?


AskDocWeb: Phendimetrazine has shown up as a false positive for Amphetamines and Ecstasy but not cocaine. Unfortunately cocaine can be absorbed through the skin so if your husband is using it there are many ways to get contaminated.

Subj: Tested positive for benzos
Date: 10/16/2008
My husband tested positive for benzo on a drug screen I know he does not take them, he was on Bactrim, Zyrtec and Motrin at the time, could this affected the drug screen?


AskDocWeb: Motrin has shown up as a false positive for THC or Marijuana but not benzos. The other two are not on the list.

Subj: GNC’s energy vitamin pack
Date: 10/16/2008
If I am taking GNC’s energy vitamin pack will it cause a false positive for anything, your input is greatly appreciated.


AskDocWeb: We can’t say conclusively but no problems have been reported.

Subj: Adderall and beclofen
Date: 10/16/2008
My son tested positive for opiates, he is taking adderall and beclofen. Could these drugs cause a false positive?


AskDocWeb: No problems have been report with baclofen but Adderall is an amphetamine and is likely to show up on most drug screens.

Subj: Positive for cocaine
Date: 10/17/2008
My name is Erik. I have been on a deferral from the court for a possesion of marijuana case. I went through the deferral no problem, all failures on my urine tests for the pharmacueticals prescribed to me were accounted for. Although, on my second to last test I was positive for cocain. This astounded me as I did not do cocain. So I have no clue why this would show up. Here are the drugs that have been prescribed to me from Dr. Arnett in the hospital. Robaxin, Hydrocodone, Ultram. I was also recieved tylenol III and lidocain in the hospital. The dosage listed on the bottle was not adequete to handle my pain. I consulted the ER at the hospital and they informed me that I could take more. I already consulted other physicians and they say it could be possible even if the confirmation screen still comes back positive. It was found in low doses in my system even though I did not use cocain. Could any of these drugs taken at high doses cause false positives for the cocain or anything else? Thank you,


AskDocWeb: Urine drugs tests seem to have a problem with both Hydrocodone and Tylenol III. Hydrocodone contains synthetic opiates (Reference 18) and Tylenol III may show up as opiates (Reference 20).

Subj: Trazodone
Date: 10/18/2008
Can taking trazodone produce a false positive for methamphetamines?


AskDocWeb: Trazodone has not been reported to cause false positives.

Subj: Tested positive for cocaine
Date: 10/19/2008
I was pre tested by quest by mouth swab for employment on a Tuesday, test came back late Friday afternoon, the employer medical review officer stated I tested positive for cocaine, I have never once used this drug, I am currently taking prescribed barbituate which has three ingredients such as fioricet, butabarbital, and also butalbital, for my headaces, I advised him of this for which he stated I was not tested for a barbitual, and my employer stated I was suppose to be tested, I am so hurt by these accusations, he also advised me that a barbituate will not cause a false positive for cocaine, I went to the hospital and took a urine test for drugs, which my result came back negative, please help.


AskDocWeb: The help you need depends on how far you want to take this. You may have to find a lawyer that specializes in employment issues. Look in the Yellow Pages under Attorney for one that advertises for Employment Law.

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