Feedback on False Positives from Drug Testing, page 50

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: Test came back negative
Date: 11/15/2008
Please help, My daughter is under doctors care for fibromyalgia, depression, she suffers very bad from the fibromyalgia. Her doctor has her on a multitude of medicines including oxycontin, flexeril, depression meds etc. She had come to him with urine burning infection, he did a urine test. Without telling her he did a urine drug test. It came back completely negative, now he is accusing her of selling her drugs, how could her test come back negative?


AskDocWeb: If the test came back completely negative then none of the drugs that the doctor prescribed are showing up on her drug test. Unless there was a mistake in the lab (small chance of that but it is possible), that could only happen if your daughter wasn’t taking the drugs.

Subj: False UA for THC?
Date: 11/16/2008
I was in a car accident, I’m taking the following medications: Oxycodone, Naproxen, Frova, Cyclobenzapine, Trazodone, Zolpidem, Citalopram, Clonazepam, Women’s One A Day, Fish Body Oil (Omega 3), Cranberry, A&D Vitamin, B6 Vitamin, Iron Supplement, Potassium Gluconate, Prunelax Ciruelax Laxative and I just got off Ciprofloxacin for a Double Kidney Infection. Would any of these Medications cause a false UA for THC?


AskDocWeb: Yes, they are listed here. Remember that it is important to get a GC/MS confirmation test as soon as possible after testing positive so that the false positive does not go on your record as drug abuse.

Subj: Zoloft
Date: 11/17/2008
Can Zoloft show up on a hair folical test?


AskDocWeb: We can’t rule out that possibility but so far it has only been reported to show up on urine tests as a false positive for benzodiazepines (Ref: 31).

Subj: Advil Venadrine
Date: 11/17/2008
Any side effect for “Xenadrine”? Also how long does advil stay in the body? This person came out positive on THC. If I do another one in two days will it still be in her system? Does the diet pill Venadrine come out positive for THC?


AskDocWeb: Advil leaves the body pretty quick so two days should be enough time. There haven’t been any reports on Venadrine and we have no data on Xenadrine.

Subj: Amoxicillin
Date: 11/18/2008
Can amoxicillin be distinguished from cocaine on confirmation methods such as gc/ms?


AskDocWeb: Yes, that is why the GC/MS test is used for confirmation, it rules out false positives.

Subj: Accident on an oilfield rig
Date: 11/18/2008
My son had an accident on an oilfield rig. His urine was immediately tested. It was clear. Then they did a hair folical test. It tested positive for marijuana. He doesn’t smoke it. I think they were trying anything to show that he was messed up that night so they don’t have to fix his arm. Is that possible?


AskDocWeb: Are you really asking if it is possible for a business to be operated by dishonest people? Welcome to the real world.

Subj: False positive for cocaine?
Date: 11/19/2008
need help, I have tested false positive for Rocanie. Never used cocanie or crack in my life. Urine test was OK & failed the hair test. The hair test results were verified using GC. Prior to this test I had a medical procedure which used Propofol, Fentanyl, Robinul & Benzocaine. Could the interaction of these medication case a false positive cocanie? Who can help, I am 100% innocent of using any form of cocanie at any point of my life.

AskDocWeb: Sorry Ron, none of those drugs have been reported to cause a false positive for cocaine.

Subj: Positive for benzodiazepines?
Date: 11/19/2008
Could Bactrim cause a positive for Benzodiazepines? Cyclobenzapr-generic for Flexeril, cause a positive for benzodiazepines?

AskDocWeb: Flexeril is not on the list, however, according to reference 60 Bactrim may test positive for benzodiazepines.

Subj: False positive for Marijuana?
Date: 11/20/2008
Would hydrocodone/APAP 5mg/500mg or Ibuprofen 600mg show a false positive for Marijuana?? I recently lost my job because of a positive drug test and haven’t touched a drug a day in my life. HELP PLEASE!

AskDocWeb: Both drugs are on this list. It sounds like you may need the help of an attorney that specializes in employment law. Did you get a GC/MS confirmation test?

Subj: Zoloft and benadryl
Date: 11/20/2008
I tested positvive for methadone. I’ve never had this medication. I take zoloft and benadryl. Can either of these cause false positives?

AskDocWeb: Zoloft has been reported to sometimes show up as a false positive for benzodiazepines (Ref: 31). Benadryl (Diphenhydramine) has been reported to show up as false positives for Benzodiazepines, PCP, and Tricyclic Antidepressants 2-4 days after a single use. (Reference 45).

Subj: Estradiol?
Date: 11/20/2008
Does estradiol cause false benzo test results?

AskDocWeb: No, none of the birth control drugs have been reported to cause any problems on drug tests.

Subj: Tested positive for crack
Date: 11/21/2008
I just found out that my neighbor tested positive for crack. He’s on Zoloft and Stretera. Can that cause a false reading or a positive result for cocaine?


AskDocWeb: Zoloft has been reported to show up as false positive for benzodiazepines (Ref: 31) but not cocaine.

Subj: Will I test positive?
Date: 11/24/2008
I had a hair test 6 days ago, 4 days before that I took 5 lortabs. They was from a prescription I had got 5 months prior. Will I test positive and will they accept my script with it being 5 months old?


AskDocWeb: The information here on false positives apply only to urine testing, not hair tests. Keep in mind that false positives occur in only a small percentage of tests so most likely you will be okay.

Subj: Bactrim
Date: 11/24/2008
Can bactrim cause positive drug urine screen?


AskDocWeb: No, the only products reported to show up as a false positive are listed here.

Subj: Drug test
Date: 11/23/2008
I injured my back yesterday and went to the urgent care clinic. I got a prescription for nalfon and one for flexeril. They gave me a Vicodin while I was there and have no paperwork on it. I just found out I have a drug test tomorrow, what can I do?


AskDocWeb: If you haven’t abused anything then the most likely outcome is that you will test clear so relax. If you don’t test clean then get a GC/MS test to confirm or deny the results.

Subj: Tested positive on new tester
Date: 11/25/2008
Hello AskDocWeb, I take random drug tests. I do not take illegal drugs and very few legal drugs. I try to avoid taking anything that I do not have to take. I also do not drink alcohol. I took a random drug test last week. Instead of dipping a stick into a cup with my urine sample, they had new testers. These were larger cups with five testers built into the side of the cup. They told me I tested positive for Methamphetamine, but tested negative for Amphetamine. He pored that same urine sample into another tester cup and got the same results. I told him to send it into the lab, because I know it will come back negative, that I had not taken any drugs. He said that is not necessary, because if I am testing positive for Methamphetamine, I should also be testing positive for amphetamine. So he just threw the sample out and did not do anything to me and told me not to worry about it. For some reason, that still leaves me feeling betrayed. I feel like my reputation has been questioned. He said he would put note in my record of the positive test and an explanation that it was believed to be a false negative. That does not seem like enough to me. I want to know why I tested positive for methamphetamine but not amphetamine. And hour before my random drug test, I had a surgical procedure performed. Very minor, it was to remove a mole from my leg. They surgically removed it–they did not use the cryogenic method. He made two injections near my mole. It was a local anesthetic which removed all feeling from that area of my leg. I’m not sure what the actual drug was, but perhaps you woudl know? I can talk to my doctor and find out what it was, if I need to. This was literally less than one hour before the drug test (about 55 minutes to be exact). The only prescription drug I take is Ranitidine for heartburn/acid reflux. I read through your posts and saw a problem with Ranitidine and amphetamines. However, I have been taking Ranitidine for 3 years now and have taken many random drugs tests during this time and never showed any positive results. All those drug tests plastic dip sticks though and this was a new test, like I described above. But it was negative for amphetamine, only positive for methamphetamine. Your comments have described issues regarding Ranitidine and amphetamines, not methamphetamine. This is very long, I wanted to make sure I provided all the detailed information I could. Yours truly,


AskDocWeb: The new rapid drug tests with the testers built into the side of the cup have a 3% error rate, which means 3 out of every 100 tests produce false positives. (source: Your test may have been one of the three. These tests are not admissible in a court of law because they provide only a preliminary analytical test result. A more specific alternate chemical method must be used in order to obtain a confirmed analytical result. A gas chromatography mass spectrometry (GC/MS) is the preferred confirmatory method. Any result taken to court, must be confirmed by a SAMHSA certified Lab.

Subj: Positive for Marijuana
Date: 11/25/2008
My wife just went through a pre-employment urine test which the employer said was negative. Then 3 days after they offered her a position a different lab, other than the initial lab she went to, called her and said the test was positive for Marijuana. Why would a different lab be calling her after the initial report to the employer was negative. Why would they keep testing a sample after it has come up negative, it was a 5 panel test? How long can a urine sample be accurate for testing? The initial report was within 5-7 days where as the second lab didn’t even notify her until 10 days after the original collection.


AskDocWeb: The best answer we can find says that a urine sample would be good for testing if it is used within 48 hours but only if the sample was refrigerated within one hour of collection. Their motivation for using a second lab is something only they can answer. We would demand a GC/MS confirmation test.

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