Feedback on False Positives from Drug Testing, page 58

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 Darvocet
Date: 3/4/2009
I am in pain managment and tested positive for Darvocet. I haven’t taken any. The night before the test I had taken Tylenol PM, and had taken Flextra-650 a few days before the test. Could one of these be the culprit? I am taking Neurontin, Lortab, and Zanaflex.


AskDocWeb: We haven’t come across a specific reference for a false positive for Darvocet but Lortab is an opioid analgesic.

Subj: Terminated from my job
Date: 3/4/2009
I was recently terminated from my job for testing positive for meth. I have never taken this in my life. I have been prescribed to xopenex inhaler and mucinex D for 6mos as well as taking over the counter vicks inhaler, alka seltzer plus cold, tylenol severe sinus, on occassion mini thins. Would these read as positive for meth?


AskDocWeb: Yes, you can see the complete list here. Did you request a GC/MS confirmation test?

Subj: False positive for Benzo?
Date: 3/4/2009
My friend has been in rehab and has to be randomly tested. He recently had the flu and was on the generic antibiotic of Bactrim, Sam’s Member’s Mark Multi-Symptom Allergy (otc med-Actifed Cold) and cough drops, which I think might have had tussin and zinc in them. He tested positive for Benzo, despite his insistence that he has been drug free. Can any of these other meds invoke a false positive for Benzo?


AskDocWeb: None of those are on the list for having caused a false positive for benzos.

Subj: i just smoke some meth
Date: 3/5/2009
Ok, my probation officer came by and i just smoke some meth earlier that mornin and the day before. he gave a mouth swab test. i advised him that i just finished drinking 2 24oz cans of beer and eating meat and homemade salsa. 5 mins after that he tested me. what r the chances i will test there anything i can say i was taking that would cover up the test.


AskDocWeb: Sorry Auggie, this information is for those who don’t abuse drugs.

Date: 3/5/2009
FOUND THE BELOW INFO @ THE JOURNAL OF ANALYTICAL TOXICOLOGY WEBSITE: Abstract: The pressure to reduce the cost of analytic testing makes it tempting to discontinue routine confirmation of urine specimens positive for drugs of abuse by immunoassay. Beyond the economic motivation, the requirement for confirmation should be driven by the positive predictive value of the screening tests. We have quantitated positive predictive values of our screening immunoassays in a large metropolitan Veterans Affairs Medical Center. We reviewed the confirmatory rate of urine specimens positive for drugs of abuse with Beckman Synchron reagents from June 1998 to June 1999 and tabulated the false-positive screening rate. There were 175 instances of false-positive screens during the 13 months we analyzed. Positive predictive values ranged from 0% (amphetamine) to 100% (THC). We determined that the low positive predictive value of the amphetamine assay in our laboratory was primarily due to the use of ranitidine (Zantac(r)). Urine specimens containing greater than 43 g/mL ranitidine were positive in our amphetamine assay. This concentration is routinely exceeded in our patients taking ranitidine. In our clinical and analytic setting, the Beckman THC assay did not require confirmation. The positive predictive values of the Beckman opiate, cocaine, barbiturate, propoxyphene, and methadone immunoassays dictate routine confirmatory testing in specimens that screen positive for these substances. Finally, because of its extreme sensitivity to ranitidine, the Beckman amphetamine assay has little utility in our laboratory setting.


Subj: Celebrex?
Date: 3/5/2009
Can celebrex cause a false positive on a drug test for benzodiazapenes?


AskDocWeb: Celebrex is not on the list of substances that can cause a false positive on urine drug tests.

Subj: Tested positive for meth
Date: 3/6/2009
I tested positive for meth and was in a DUII program. Up to that point I had been clean except I am on valium, klonipin, oxycodone, robaxin, which always tested within prescribed range the whole time. I asked my Doctor for something to help me sleep that was nonaddicting and he gave me hydroxyzine 10mg tablets. It was not helping me so I was taking 2-3 tabs until I could see my doctor again. Is it possible that caused my positive test? Thank you,


AskDocWeb: So far there have been no reports of hydroxyzine showing up as a false positive but that doesn’t mean it is impossible.

Subj: Stadol or Phenergan?
Date: 3/8/2009
Can Stadol and/or Phenergan cause a false positive in a drug test for opiates?


AskDocWeb: There is nothing on Stadol but Phenergan-D has been documented: See reference 18.

Subj: False positive for LSD?
Date: 3/8/2009
Can Trazodond (also known as Desyrel) give a false positive for LSD?


AskDocWeb: No, there are no reports or references for that happening.

Subj: Ibuprofen
Date: 3/10/2009
Can ibuprofin cause a false positive for cocaine?


AskDocWeb: Ibuprofen has been reported to sometimes show up as a false positive for Marijuana but not cocaine.

Subj: Shocked the first time
Date: 3/10/2009
I am on probation and have now tested positive for cocaine three times via a saliva test. I was shocked the first time but gave the probation department the benefit of the doubt since some of my friends used. After the second test I was really pissed off because I knew I wasn’t around anyone who used but once again just assumed somehow I had come in contact with it again. So my P.O told me next time I tested positive he was going to arrest me. I was given a saliva test again and tested positive again for cocaine! I was furious and tried to plead my case but he did not want to here it. He told me I have a problem and need to get into a residential drug program or he was going to arrest me. Here is the kicker…The same day I went to another clinic and had a hair follicle test done. The RESULTS WERE NEGATIVE FOR EVERYTHING. I contacted my PO and he told me if I wanted to fight it I would have to do it from jail since I wasn’t being compliant with his orders. My lawyer says it will be hard for me to fight this case from in jail and I definitely agree. And the problem is I didn’t take action the first two times and those tests were three to four months ago. So he thinks I have a weak case and should just do the program. I don’t want to do the program though because I don’t have a problem, it costs $9k, and I would have to quit going to school and quit my job. What should I do? I am innocent!


AskDocWeb: Not contesting the results of the first two tests puts you in a bad situation. That makes it difficult to fight and very little hope of winning.

Subj: I tested positive for amphetamines
Date: 3/11/2009
During a random urine drug screen at my job, I tested positive for amphetamines. The only medication I am currently taking is Neomycin and Polymyxin B Sulfates and Hydrocortisone OTIC Solution, USP and Hyland’s (over the counter) Earache Drops for a severe ear infection. Could one of these have caused this positive result?


AskDocWeb: Sorry Karrie, none of those are on our list.

Subj: Test came back positive
Date: 3/11/2009
Hi, my father had to go in for a drug test for his job. He came up with a 24ng on one of them and we are not sure what that means. I know my father does not do drugs so we can’t understand how it came back positive and now he may lose his job. I never thought that certain things could cause a positive test. The only things my father is taking is 2 tabs of Ibuprofen 600 mg per day, centrum vitamen, vitamen C and vitamen B. He just recently had hernia surgery so there will be added things on top of this. But could any of the above cause him to fail a drug test? The other question I have, they now want to do a hair test. But if something is showing up in the urine won’t it also show up in the hair as a positive test? I’m confused.


AskDocWeb: Both Ibuprofen and vitamin B2 have shown up as a false positive for Marijuana (THC) (Ref: 1, 3, 16, 18, 29). The hair test is a different kind of drug screen and doesn’t have the same false positives.

Subj: Positive for PCP
Date: 3/11/2009
Hey I am a 25 y/o female with bad back pain, I have been seeing a pain doctor for almost a year now, the did some blood work a few weeks ago and I just found out the it was positive for pcp and methadone. I have never taking either of these. I however did take the following: abeien, alprazolam, wellbutrin. I also was taking Toradol in the month my blood work was done. Could any of this made it a false postitive? or they just mixed my blood up? HELP PLEASE this caused my doctor to discharge me.


AskDocWeb: Sorry Christy, the only drugs that have been reported to show up as PCP are Diazepam, Diphenhydramine, Effexor, and Ketamine.

Subj: Zolpidem Tartrate?
Date: 3/11/2009
My husband attends a methadone clinic and recently tested positive for benzodiazepines. Can Zolpidem Tartrate make him false positive for benzodiazepines? What other drugs can cause a false positive for this? Thank you.


AskDocWeb: Zolpidem is not on the list of substances that cause false positives in urine tests. You can check the complete list here.

Subj: Tested positive for THC
Date: 3/12/2009
I use nasal spray and sleep-aids often and the past few months I’ve had trouble getting rid of a head cold and sinus pressure. I’ve taken everything from claritan, benadryl, sudafed, goody-pm, 800mg ibuprofen for headaches etc. Recently I was selected for a random drug test(mc/gs or something like that) and tested positive for THC. My response was it has to be a mistake! Please tell me I’m right, my job is on the line.


AskDocWeb: We can’t tell you that you are right. The GC/MS test is not subject to the same errors as the cheaper panel tests.

Subj: Cocaine in my hair
Date: 3/12/2009
I recently had to take a hair folical Drug test. I am not a drug user. And the test came back that I had cociane in my hair. I would like to know how and why would it come back positive if I dont use the drug. I would like someone to contect me. I am being falsely accused and would like my name to be cleared. Can you help? Please let me know, thanks.


AskDocWeb: Sorry Francine, that is beyond the scope of what we do here. Our information is limited to urine drug testing.

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