Questions about False Positives in Drug Testing, page 242

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.

Judge ordered evaluation
I recently won the right to move to a new school district with my 8 year old daughter. The past year I have had to take pain medication aftre a neck surgeruy and delay in getting better due to lack of medical Inc. My childs father made all sorts of claims about me being on all sorts of drugs. There was no proof but since I did have medications with doctors note the judge thought it best to have an eval done anyway. So I did.

I handed over my pill bottles and told them my history. I said I rarely drink this past year, mostly due to the pain and medicins. I made a comment that in the past year I may have had 4 drinks, the last one one week prior to our meeting. The councler said everything sounded good and probly get a 8 hour long class if that.

Well after 3 UAs all coming up normal to what was in my systems with my pills, they said the 3rd UA had alchol in it and that makes me a liar and I need first level treatment starting costs 500.00 and UAs and meeting weekly. I was so mad I have been trying ti call the person who did the report to ask why these error were in teh report and why she did ask me about how I never had a drink until after 6-7 hours after a pain pill. I had called my pharmasist for that info. She wont take my calls, she wont return my calls. Than to top it off she wrote me up for concern about my adderal. she wrote it as 20mg a day when the bottle clearly says 40 mg a day. WHAT DO I DO – This is my life with my daughter I have fought so hard to be with me. My Inc company advised me to get a second opinion. But the lady who did report already sent to courts. Any help?


AskDocWeb: It sounds like you are going to need legal help. Have you consulted with a Lawyer?

Secondhand cocaine?
Can a person test positive for an illegal substance when they are clean, but their partner is a user of cocaine. Not by injecting, but by snorting it?


AskDocWeb: Yes, since cocaine can be absorbed through the skin, you are at risk from secondhand exposure. (

Today i took a drug test for my probation officer and i tested positive for a drug called BUP and TCA but i havent took any drugs what so ever the only thing iv done close to a drug was marijuana but that was about 4 weeks ago but i tested negative for that


AskDocWeb: BUP is short for Buprenorphine and the TCA stands for Tricyclic Antidepressants.

Tramadol metoprprol vicodin advil sudifed ranitadine


AskDocWeb: What about them?

False positives for benzodiazepines?
I am attending a methadone clinic for help with weening & eventually stopping my past use of morphine and oxycontin (for 15 years+) as a method of pain relief. I’ve had one year and a half of clean UAs and, thusly, had accumulated the status of one who only had to travel to the clinic once a week for medication.

As of earlier today I’ve lost that status (even though I had another come back clean since the test in question) for the time being, due to a false positive for bezodiazapines, for what has to be taking benadryl. This will interfere with my ability to get to work on time and I’d like all info to help myself fight for what I’ve worked so hard to earn.

What exactly will benadryl come back positive for? Anything more specific than just the broad defenition of general benzodiazapines would be helpful in discrediting a shoddy organazation’s test results. Also, what level (or however it’s measured) might the test typically come back at if the recommended dosage is taken one time 1-2 days prior to the urine analasys? My feeling is that it would have to be very, very low… Thanks for your help.


AskDocWeb: Benadryl (Diphenhydramine) may show up as false positives for benzodiazepines (such as Xanax or Valium), PCP, or tricyclic antidepressants. In order to discredit their positive test result you need to get a GC/MS confirmation test. The EMIT urine tests typically show only a yes or no result for the presence of drugs of abuse. The GC/MS confirmation test will give a quantified answer as to exactly how much, if any, drug is in the sample.

False positive for cocaine?
I was screened for illegal drugs and my result came positive cocaine. I am taking tablets for epilepsy Keppra, epanutin, and thyroid tablets levothyroxine and high blood pressure amlodipine tablets and Valium Suppositories. i also smoke electronic cig, redbull flavour. can cause a false positve for cocaine? Or other illegal drugs?


AskDocWeb: Sorry Jonathan, none of those would explain a positive test for cocaine. The only medical conditions associated with false positives for cocaine are kidney disease and diabetes.

I tested positive for PCP
I am taking Lamictal, Effexor XR and Lorazepam. I tested positive for PCP on a 5 panel drug screen. I opted to go to the clinic for a lab test. Will I still test positive on that test? I dont do drugs so I know it has to be my medication.


AskDocWeb: That depends on a couple of things; what type of lab test they do and whether or not your first test result was a false positive. Sources at the Baptist Medical Center Downtown Jacksonville, FL say that Lamictal and Effexor each might cause a false positive for PCP. If they are doing a GC/MS confirmation test then that should clear things up.

I’ve seen reports that say that Zyban can cause a false positive for amphetamine on a drug screen (Immunoassay), but it doesn’t address GC. Can Zyban still show up as amphetamine on a GC?


AskDocWeb: According to the US National Library of Medicine National Institutes of Health, “Therapeutic use of bupropion (Zyban) appears to be the most frequent cause of false positive urine drug screens for amphetamines in our population.” This refers to the use of the Syva EMIT II immunoassay. Link

Bupropion is marketed under the following brand names:

  • AplenzinTM
  • Budeprion SR®
  • Budeprion XL®
  • Buproban®
  • Wellbutrin®
  • Wellbutrin SR®
  • Wellbutrin XL®
  • Zyban®

We have seen no reports of the GC/MS test misidentifying bupropion as amphetamine. In all the reports we have read, bupropion false positives were ruled out with the GC/MS confirmation test.

Zyrtec false negative?
I don’t have a product review but I do have a question. As the parent of a teenager I do my best to stay informed on the various drugs out there. One thing I keep hearing is that by taking Zyrtec, it will cause you to test negative for marijuana. I’m a nurse, & have never heard such a thing but now has me concerned! Thank you for any help you can offer!!!


AskDocWeb: False negative results caused by Zyrtec do occur but not for drugs of abuse. The only examples we could find were in response to allergy skin tests. If a patient has taken an antihistamine within 5 days of allergy testing, this may cause decreased responses to allergy skin tests. This applies to both long-acting and short-acting antihistamines (e.g. diphehydramine, hydroxyzine, chlorpheneramine, loratidine, ceterizine, fexofenadine)

Source: Allergy Assessment in the Primary Care Setting by Frederick M. Schaffer, M.D., Clinical Associate Professor, The Medical University of South Carolina.

My urine was clear
I take medications oxycodone and clonipin and I had to take a test to test the levels in my system. When I went to take the test my urine was clear. I have been drinking water due to being sick. If my medication shows up will they still say it is diluded?


AskDocWeb: Sorry Genna, there is no way to predict that. You might try keeping track of how much water you are drinking and discuss this with your doctor.

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