Questions about False Positives in Drug Testing, page 202

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.

Saliva test?
Date: 5/18/2012
Combination of drugs… I was wondering if the combinations of zonegran amitryptaline and divalproex can create a false positive on a saliva (drug) test…


AskDocWeb: We have found no cases in which a combination of drugs produced a false positive unless at least one of the individual drugs did that.

Neither Zonegran (Zonisamide) nor divalproex are reported to cause false positives however, amitryptaline has shown up as a false positive for LSD and Tricyclic Antidepressants (TCA).

Date: 5/18/2012
I have been a life long smoker of marijuana,i stoped 3 months ago to get a union job..I went for my piss test three days ago,mind you i havnt smoked in three months,and i faild my test…how is this possible? the doctor called me and told me he found 31 nanograms in my urin,and i just couldnt imagin how . like i said i havnt touche a thing in 3 months so how is this possible?


AskDocWeb: Over time, long term users build up more of the metabolite in their system, which takes longer to eliminate. Detection times vary from one individual to the next depending on the drug potency, tolerance, and health condition of the person being tested, fluid intake at time of test, method and frequency of marijuana use. Although it is usually not more than 15 to 20 days there are reports of some people testing positive for as long as 15 weeks after discontinuing.

UAs came up positive
Date: 5/18/2012
I have to take UAs and have not taken any pain killers or done any drugs. But one of my UAs came up positive for opiyets. I ate a poppy seed bagle that day. Could that be my faulse positive.


AskDocWeb: There are several sources that say poppy seeds can make a urine test positive for Opiates. (References: 3, 16, 17, 20, 21, 25,
26, 29, 32, 48, and 60)

Positive for propoxyphene
Date: 5/19/2012
I currently underwent a drug test at work that came back positive for propoxyphene in an unusually high dosage. Since I took only 1 the night before the test I am a little confused by this. I realize it was pulled from the market but I still had a few from an old and honestly thought they would only show up as an opiate, they were not in the original bottle. Anyway, I am on wellbutrin, lisinopril, source of life energy enhancing vitamin, coreg, mobic and zyrtec daily but in addition I had taken a z-pack, mucinex, dextromorphan, sudafed, and phenlyphrine for a cold. Do you if any of these medications would have enhanced the drug in my system?


AskDocWeb: Since you took one the night before the test, the test result was not a false positive. Having a lot of other drugs and toxins in your system would slow down your body’s ability to metabolize and eliminate the Propoxyphene.

Positive for heroin?
Date: 5/20/2012
Plz help how is it possible I test negitive for cocaine amphetimines opiates codine but positive for heroin? plz I need a answer fast I don’t understand at all? My kids have been removed from my care for this reason help court very soon!


AskDocWeb: Each of the drugs you list leaves different chemical waste products or metabolites when used in the body. The drug test is designed to detect those waste products. The specific metabolite of heroin is 6-monoacetylmorphine (6-MAM). Because 6-MAM can originate only from heroin, its detection in the urine means that the patient used either heroin or 6-MAM.

If you believe that your drug test result was a false positive then you need to know that getting a confirmation test, typically a GC/MS test, from a certified lab is the only way to prove that it is indeed a false positive.

False positive for barbiturates?
Date: 5/20/2012
I take Zanaflex. I am in rehab and the only thing I am taking is Suboxone and Valproic Acid. I have taken Zanaflex when it was prescribed for me but, since being in rehab and on the Suboxone, I’m not supposed to take the Zanaflex but I have on a couple of occasions due to muscle spasms in my back and legs (I am a chronic pain patient). Every time I take a drug test, it comes back with a positive for barbiturates but, my hand to God, I have taken NOTHING other than the Suboxone, Vaproic Acid, and occasionally the Zanaflex. Would the Zanaflex come up as a barbiturate in my drug screen? Or the Suboxone? I am so tired of peein’ in a cup every time I go to Group because of something that keeps coming up in my system as a barbiturate. Please help clear this up for me. I’m desperate!


AskDocWeb: Zanaflex (Tizanidine) is an alpha-2 adrenergic agonist, a type of drug that inhibits muscles by stimulating motor neurons in the spinal cord called alpha-2 receptors. Simply put, it turns on neurons in your spinal cord that turn off your muscles. It has not been reported to cause false positive urine tests. Here is a list of substances the have been reported to sometimes show up as a barbiturate:

  • Allobarbital
  • Alphenol
  • Amobarbital
  • Amytal
  • Antiasthmatics that contain phenobarbitol
  • Aprobarbital
  • Barbital
  • Butabarbital
  • Butalbital
  • Butisol
  • Dilantin
  • Donnatal
  • Donnatol (for irritable bowel syndrome)
  • Fenoprofin
  • Fioricet
  • Fiorinal w/codeine
  • Luminal
  • Nalfon
  • Nembutal
  • Pentobarbital
  • Phenobarbital
  • Phenobarbitone
  • Phenytoin (Dilantin┬«)
  • Primidone (Mysoline┬«)
  • Secobarbital
  • Seconal
  • Soneryl
  • Tuinal

Of course if any of these showed up as a false positive on your urine tests you would need to get a confirmation test to clear yourself.

Kris again
Date: 5/21/2012
I previously posted on this forum but don’t see my post so I’m trying again. I had to take a urine screen drug test and it came up positive for barbiturates. I am currently taking Suboxone, Alporic Acid, Zanaflex, Pristiq, Abilify, and Phenergan. Would any of these prescription drugs bring up a false positive for barbiturates?


AskDocWeb: Your original post was answered above. Sometimes it takes a few days for a post to make its way through the system. And yes, we do take time off occasionally.

Date: 5/21/2012
I haven’t taken anything except amoxicillin and I am coming up positive for benzos? Is that possible?


AskDocWeb: Amoxicillin has shown up as a false positive for cocaine but not benzos. However, there are almost 60 other possible substances that could cause a false positive for benzos so if you haven’t used any we suggest you get a GC/MS confirmation test from a certified laboratory.

Date: 5/21/2012
Hi, I have query about Misoprostol. Is the product still traceable in your urine after taking them two weeks ago. Thanks for all answers.


AskDocWeb: That is highly unlikely. Misoprostol has a very short half-life of 40 to 60 minutes. All trace of the drug is completely eliminated from the system after a 4-day washout period.

Secondhand marijuana smoke
Date: 5/21/2012
If I was around someome that smoked marijuana outside the day before drug test would it show up on my urine analysis?


AskDocWeb: Although it is unlikely it does increase your risk of testing positive.

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