Feedback on False Positives from Drug Testing, page 49

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: I’m baffled
Date: 10/31/2008
I was recently tested on an oral swab for narcotics and it came back with a very low positive for Benzoylecgoine. I take several prescription drugs including vicodin, prednisone, asacol, bentyl. Not to mention other IV medications including steroids for my colitis. I also used a prescription denture numbing agent that my dentist gave me called Benzodent, could this cause this level to be rasied to 15.5ng/ml. Please help me I’m baffled as to how it is showing up as cocaine. I haven’t used.


AskDocWeb: The only one we would suspect is the Vicodin because it contains synthetic opiates. Be careful with your dental appointments as the Novocain your dentist uses may show up as a positive for opiates.

Subj: Positive for meth
Date: 10/31/2008
My son is in jail because he tested (urine test) positive for meth. He’s been taking Excederine, sudafed, benadrill for headachs, headcolds, and stuffy nose. Would any of these meds show up as a false/positive for Meth. Thank You.


AskDocWeb: Yes, it is possible that the Sudafed could show up as meth on urine tests.

Subj: Tested positive
Date: 10/31/2008
Please help I have never used cocaine and have tested positive for it -I have hep c and b and was in the hospital 2 months ago for a kidney infection I read liver and kindney infections can cause this what test do I need to prove that fact?


AskDocWeb: It is called a Gas Chromatograph/Mass Spectrometer (GC/MS) confirmation test.

Subj: False positive for phenobarbital
Date: 11/1/2008
I tested positive for phenobarbital. I’m a RN and I never ever take phenobarbital in my life. I do take topamax q day, motrin 800mg q day, ultracet prn. I was taking phentemine q daily. vit b 12 shots. Please let me know if any of the drugs would cause a false positive for phenobarbital.


AskDocWeb: According to The Encyclopedia of Addictive Drugs Fiorinal is known to produce a false positive for phenobarbital in body fluid testing. Remember that a false positive can occur with any test and questionable results should be followed up with a GC/MS confirmation test.

Subj: Prescription proof
Date: 11/3/2008
I tested positive due to a prescription drug, that I had listed I was taking when I took my urinalysis. The testing agency requested I get proof of the last time I had the prescription filled. Is this common practice and how do I obtain such a form? Is there a term for this form?


AskDocWeb: Not sure how common this is but the pharmacist where you filled the prescription can provide you with a copy of that prescription.

Subj: References
Date: 11/5/2008
What are the ref. numbers that you have listed after medications or conditions that can cause false positives. I recently tested positive for meth and should not have. I have diabetes and am trying to fight this but I cant find any information other then a lists with ref. that I cant see.


AskDocWeb: There are links to the reference page at both the top and bottom of the list or you can click here.

Subj: References
Date: 11/5/2008
I am looking for some sort of medical proof to the claim I found on your website (Amoxicillin – false positive for cocaine) I did not understand what the (Ref: 13, 16, 18, 20, 21, 26, 29) is refering to.


AskDocWeb: Okay, in order to make this easier for you, we went through all the references and made each one a link to the reference page.

Subj: Positive for meth
Date: 11/5/2008
My brother took a Zantac 150mg about 2 hours before going for a drug test and it came back positive for meth; it was a urine test with a stick dipped in the urine; the urine is suppose to be sent to a lab for further testing will the further testing show up as zantac or will it still show up as meth?


AskDocWeb: That depends on what they mean by further testing. If it is the GC/MS test then it should show the difference Zantac and meth.

Subj: Tested positive for cocaine
Date: 11/6/2008
I am currently taking Guaifenex, Levaquin, Prednizone, Xanax, Celebrex, Nexium. I recently tested positive for cocaine. Would any of these drugs or combination of these drugs cause that. Thanks,


AskDocWeb: Sorry Bob, none of those show up on our list.

Subj: False positive for hydrocodone
Date: 11/6/2008
What causes a false positive for hydrocodone in a urinalysis? My doctor recently took a drug test and it came out positive for hydrocodone. She said I am getting prescriptions from some one else and does not want me to come back to her practice. The only medications I take I get from her. I have fibromyalgia and am taken the follow medications prescribe by my doctor, trazadone, effexor, estrogen, endocet (perocet), oxycontin, iron pills, ondansetron, albuterol, astelin and thyroxin. I am very upset about this.


AskDocWeb: The closest we can come to what you list is Percocet. It will test positive (not false) for opiates (Reference 3 and 20).

Subj: Saliva test
Date: 11/8/2008
Can atenelol or estrogen cause a false positive on a drug test? It was not a urine test but the test where they use your saliva.

AskDocWeb: Sorry Jane, almost everything you see here refers to urine tests. We have very little data on false positives on saliva tests.

Subj: Celexa?
Date: 11/10/2008
Can taking celexa produce a false positive for cocaine or marijuana & what can cause a false positive for these drugs any food perhaps?

AskDocWeb: We have had no reports of Celexa showing up as a false positive on urine tests. Everything that has been reported to cause false positives (so far) is listed here.

Subj: Elavil
Date: 11/10/2008
Can elavil cause a positive drug screen for opioids?

AskDocWeb: Yes, Elavil has been reported to show as a false positive for opiates for up to three days (Reference: 3, 26, and 29).

Subj: False positive because of diabetes
Date: 11/11/2008
Hi, I was wondering if you’ve had a false positive test because of diabetes will you always test positive?

AskDocWeb: No, as far as we can tell, it only happens in a small percentage of cases when urine testing is used but exact numbers do not seem to be available. You have to remember that this is somewhat of a taboo subject. So much effort is put into avoiding the appearance of aiding drug abusers that professionals are reluctant to share data. Unfortunately that leaves those falsely accused out in the cold.

Subj: Smoking
Date: 11/11/2008
I Have a drug test comming up any week now and I have stopped smoking for almost two weeks if I have been drinking water also taking b12 and ginsa gold vitamins should it be out of my system by now?

AskDocWeb: What were you smoking, tobacco, marijuana, or something else? In general you would need about 30 days to clear your system for a urine test. If they use a hair test you may be out of luck.

Subj: Positive for Benzodiazapines
Date: 11/12/2008
I have been in treatmant (rehab) for 5 months I then transitioned to a halfway house. I have not used any narcotics. I was given a random urine drug screen and I failed testing positive for Benzodiazapines. The only medication I was on was Lithium, topomax, vistiral, cymbalta, propananol, trazadone, motrin 800, and I had a shot of lidocaine for a minor surgical procedure earlier in the day. Why would I test positive? Please help, I got kicked out of halfway and lost custody of my daughter. I don’t know what to do.


AskDocWeb: Getting a GC/MS confirmation test as soon as possible after you receive a false positive is the only way that we know of to prevent that from happening.

Subj: Energy drinks
Date: 11/12/2008
I wanted to know what all supplements that can cause a false positve for cocaine. My husband lost a job after 11 yrs and he had 2 engery drinks that night the last one one hour before the test it was a monster assualt. My husband has never tested postive for anything and after hundreds of random ua’s now he’s did…he’s been clean since he was a teenager so I don’t understand.


AskDocWeb: There seems to be a growing concern that energy drinks might cause a problem in urine testing but so far no documented cases have shown up.

Subj: Butalbital
Date: 11/13/2008
Is there any medication that can lead to a false positive of butalbital in a drug screen? Over the counter or prescription?


AskDocWeb: So far none have been reported.

Subj: CVS first check drug test
Date: 11/13/2008
My boyfriend is a recovering crack user. Tonight I gave him a CVS first check drug test. He failed coc and thc. I know he has smoked weed. Is he lying about crack? He’s also on suboxone.


AskDocWeb: That is difficult to tell. The best way available to find out for sure is the GC/MS test to confirm or deny the results. Suboxone is a new drug and we have no data on how it affects urine tests. It is an opioid or opiate, which means that it contains or is made from the narcotic opium.

Subj: Freaking me out
Date: 11/13/2008
I have been taking prozac and some antibiotic and I tested postive for opiates twice now…do any medications show a false postive for opiates cause I’m in drug court and it’s really freaking me out cause I have been clean and sober for about 5 months now so I don’t understand why I am failing my drug test…please help me figure this out it’s driving me crazy.


AskDocWeb: Yes, you can check the current list here.

Subj: Pepcid
Date: 11/13/2008
I have found that Zantac can cause a false positive for amphetamine test. Do you know if Pepcid will also cause a false positive?


AskDocWeb: Pepcid is not known to cause false positives on drug tests.

Subj: Cocaine?
Date: 11/14/2008
My fiance is in the military and he had a terrible cocaine problem for years. He slowed down before entering the military and stopped totally before he was deployed in Jan 2008. He did have an injury to his neck durning a humvee exercise back in December of 2007. The doctor’s at Fort Dix prescribed him vicodin. He took a urnine test around Jan 20th 2008 and he’s telling me he popped for his pain meds but the test is saying it’s not the pain meds he’s popping the test for it’s cocaine. Is that possible? He claims the opiates in the vicodin make it look like he was using cocaine. I need to know if he’s lying to me and used again. Is there a way they can tell by a different analysis what is in his system.


AskDocWeb: Yes, the different analysis is called a Gas Chromatograph/Mass Spectrometer (GC/MS) confirmation test.

Read more feedback about false positives:

Read Previous
This is page 49 – NextLast Page 300

If you find this page useful share it with others. All new questions will be answered by Doctors online.