Questions about False Positives in Drug Testing, page 233

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 positive for alcohol
I’m on probation and they recently began using salvia test instead of urine screening. i have been sober for 18 months, and recently i was positive for alcohol. i am adomant about using listerine zero. is there any insight you can give me


AskDocWeb: Any person that is subjected to or relies on EtG testing should read the Advisory issued by the US Department of Health and Human Services. Although it is dated September 2006 it remains in effect today.

Tested positive for marijuana
My Daughter just tested positive for marijuana she doese not use it she is preganat! What over counter drug or can a urinary track infection or vitamins or ibuprofen 800 ml cauese it to happen?


AskDocWeb: This happens more than you might think and reports from employees at some hospitals say that false positives from Ibuprofen are common. According to the Lectric Law Library (Drug testing in the Workplace), Ibuprofen is known to cause false positives for marijuana on urine drug tests. This has been confirmed by Medimpex United, a wholesale distribution center for Rapid Drug Test Kits. Of course there are also over 70 other possible causes for a false positive for marijuana. Government guidelines recommend doing a confirmation test on non-negative test results.

False positive for phenobarbital
I tested pos for phenobartital. i have never taken that drug ever dnt wat it is. wat can cause this. i take benadryl, advil, thats it. im am beyond confused. are there any chemicals that could do this. my level was under the cutoff of 200


AskDocWeb: According to the Encyclopedia of Addictive Drugs Fiorinal is known to produce a false positive for phenobarbital on urine drug tests. If you get a confirmation test, the GC/MS will prove that it was a false positive.

Drug screen didn’t show drug
I take anatripline and hydrocodone, levathrocen(thyroid), prvacid. I had to have a drug screen for a weight loss surgery. My test found the anatripline but no hydrocodone in my urine. Why?


AskDocWeb: Like it or not, the most common reason for a drug not showing up is that the patient didn’t take it as directed. However, there are other reasons for this to occur:

  • The dosage may be too low to show up.
  • The last dose taken may have been taken too long before the test.
  • The sensitivity level of the test may have been too low to detect the drug.
  • Some patients have a high metabolism that clears the drug from their system faster than expected.
  • The test may have been faulty or past its expiration date.
  • Human error on the part of the person conducting the test.

Although rare, it is also possible for a combination of the above events to produce a negative test result.

Drug screen coming up
I am on potassium chloride 10meq ERCAP, advir 250/50, lisinopalril and hydrochlorothiazide 20/25,pravastatin 40mg.neb-Albuterol 0.83% I have a drug screen coming up and want to know if any of these meds will throw it off. I need this job.


AskDocWeb: Welcome Veronica. None of those are on our list of possible causes for a false positive drug test. However, there is still the possibility of human error and other unknown causes so be prepared to get a confirmation test if you need one. Good luck!

Meth from intercourse?
I have not used any illegal drug and I tested positive at a very low level for meth. My boyfriend, at the time, still used meth. He would snort it. We had intercourse approx. 4 hours before I took the UA, not even thinking it would affect my UA. I had a GC/MS screen done and it came back positive for meth, again at a very low level. The toxicologist says it is consistent with me being in the room with others smoking meth but that has not happened. Could it have been passed to me from intercourse?


AskDocWeb: We have not seen any clinical evidence of that be it is theoretically possible. Unless you have another explanation for the meth in your system, we suggest you give careful consideration to your situation and how it might affect your future.

False positive for methadone
I had a blood test and tested positive for methodone but never touched the stuff. Please inform me why this would happen because there is alot in jeopardy with this false reading. I do take medication for arthritis (tramadol, hydrocodone, prednisone) asthma (ventolin inhaler) and high blood pressure (lisinopril). Please help me understand why this false positive for methodone occurred when I have never ever taken methodone. Not sure what to do to prove this is a false reading. Please advise me and thank you for your help with this matter.


AskDocWeb: The list of possible causes for a positive for methadone is pretty short:

  • Antihistamines in general
  • Bentyl
  • Elavil
  • Methadose
  • Nyquil
  • Phenergan
  • Physetone
  • Vicks Formula 44M

In order to prove that test result is a false reading you have to dispute the results of the drug test and get the sample re-tested with a gas chromatograph mass spectrometer. This method has the ability to distinguish the exact substances present in the sample. This is often a follow-up option for those facing serious consequences such as a job loss or jail time. Good luck!

E cigarettes
I currently began smoking an e cig and tske random urine tests for parole which all get spun at the lab the ingredients in them are vegetable glycerin, propylene glycol, alcohol, liquid nicotine and flavoring. I get tested for everything even alcohol will these products give me a positive? One is made by electronicstix and other by high caliber e liquid. Thanks.


AskDocWeb: To date there are no reports of any kind of false positives on urine drug tests for drugs of abuse from those using e cigarettes. Of course this does not guarantee that you will pass the drug test. False positives occur for many reasons.

Parole testing
on parole do they test you for anabolic steroids? or human growth hormones?


AskDocWeb: If you’re the one on parole and need to know this then ask your parole officer.

Hi, I got a DWI and was court ordered not to drink any alcohol and would like to know if Kava would make me have a false positive for alcohol. Thank you in advance


AskDocWeb: No.

Tested positive for Oxy and Propoxyphene
I recently took a urine test at work and tested positive for Oxy and Propoxyphene. I’ve NEVER taken either. I took 3 of my prescribed Norcos the morning and day before. Is it possible that they called a false positive? The urine was sent to a lab, but I don’t trust anything once it leaves my presence. Should I worry?


AskDocWeb: If the lab is doing a GC-MS confirmation test then it will eliminate the false positives so if you are clean you can relax.

False positive for propoxyphene?
If I had a prescription of 16 Norco on 7/29 and took two last week because I only used them when I needed, is that against how I’m supposed to take them? How long is a prescription good for? Will Norco cause a false positive for propoxyphene?


AskDocWeb: The length of time that a prescription is good for varies so you will have to check with your doctor on that as well as how you are supposed to take them. In researching your question we found two antidotal reports of false positives for propoxyphene but there was no documentation to determine a specific cause. As always, if you suspect that your drug test produced a false positive result, then get a confirmation test from an independent laboratory.

Flse positive for propoxyphene
What can cause a false positive for propoxyphene? Does hydrocodone/APAP contain propoxyphene? Is Norco the same as hydrocodone/apap? Thank you


AskDocWeb: The chemical structure of diphenhydramine (Benadryl) is similar to d-propoxyphene so it is possible that might show up on immunoassay analysis resulting in a false-positive for propoxyphene. There are antidotal reports that poppy seeds, couch suppressants that contain Dextromethorphan (DXM), Methadone, Nyquil, kidney infection, kidney disease, diabetes, and liver disease may also show up as propoxyphene on urine tests.

Hydrocodone/APAP does not contain propoxyphene. Norco is a combination drug containing acetaminophen and hydrocodone.

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