Feedback on False Positives from Drug Testing, page 80

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: False positive for syphilis?
Date: 12/13/2009
I recently had a false positive result for syphyllis when I donated blood. It has only been recently and I have donated blood for 20 years. They said it could be a reaction with some medication. The only think that I have done different recently is to take Alli for weight loss and take Ranitidine for acid reduction. Could either of these cause this result? I have never been sexually active with anyone and this is troubling me.


AskDocWeb: A screening test alone can not determine whether a person has syphilis or not. Any positive results need to be confirmed with a treponemal test (fluorescent antibody or hemagglutination) because false positives occur for a number of reasons. Here are a few:

  • Auto-immune disorders (such as SLE. About 20% of SLE patients test false positive for syphilis.)
  • Multiple Sclerosis, an illness similar to Lyme disease
  • Intravenous drug users
  • Chronic liver disease
  • HIV infection
  • Lupus patients can produce antibodies which are close to the antibodies against syphilis, making it possible to show a false-positive for syphilis without having the disease.

Overall false positive tests for syphilis occur in 1% – 2% of all those who are tested.

Subj: Medicines with Hydrocodone
Date: 12/14/2009
I am allergic to hydrocodone. It causes itching (no rash), a headache, and vomiting. My doctor prescribed a cough syrup for me. I began itching and looked it up online and found it had hydrocodone in it. Where can I find out what all kinds of medicines have hydroconde in it?


AskDocWeb: Since this is not about False Positives, we put your answer here.

Subj: Pre employment drug screen
Date: 12/14/2009
Doc Web, I really need your assistance. I have recently taken a pre employment drug screen and found out 5 days later it tested positive for cocaine. 15 years ago, I would have let it slide but not now. It’s been that long since I’ve touched it. Could the medication I’m on along with what I drink give me false positives? I’m on Tylenol 3, Ranitidine, take Sudafed for my sinuses and have a couple of vodka/tonics. Please help.


AskDocWeb: Several of the Tylenol products have been noted to sometimes show up on drug screens as opiates. The help you need would seem to be a GC/MS confirmation test. This is the test they use when your sample is sent out to a lab for confirmation.

Subj: Tested positive for morphine
Date: 12/15/2009
I ate poppy seed cake and tested positive for “morphine.” I do not take any type of drugs like this. I have only occasionally taken tylenol or regular asprin. Can you explain how I could test positive for morphine???


AskDocWeb: Yes, poppy seeds contain morphine. Depending on the source, the amount of morphine in the poppy seeds can range from 2 to 251 micrograms per gram.

Subj: Positive for meth by eating shellfish?
Date: 12/15/2009
Can you test positive for meth by eating any kind of shellfish? What about if you took theraflu? By the way I love your site and these are really good to know facts if you’re on probation.


AskDocWeb: Although some shellfish can contain some pretty exotic chemicals there are no reports of any false positives caused by shellfish. So far, there are no professional references that say Theraflu might cause any false positives.

Subj: Amino 1000 softgell tablets
Date: 12/15/2009
Can amino 1000 softgell tablets cause a false positive on a drug test for any drug?


AskDocWeb: We can’t prove a negative but at least there are no reports of any false positives caused by Amino 1000 soft gel tablets.

Subj: Adderall without a prescription?
Date: 12/16/2009
Two days after taking a single Adderall xr w/out a prescription I was randomly drug tested at work, I recieved a call from the lab today, I haven’t returned the call yet but I will be interviewed by the tech prior to them turning the info into my EAP Counselor at work, my question is, should I just admit to taking the Adderall without a prescription or try to say it was Nyquill or something like that. It definitely wasn’t Meth.


AskDocWeb: Sorry Joe, we can’t help you with this one. Either way you do, it sounds like you may be in trouble.

Subj: Anything OTC or Rx?
Date: 12/16/2009
I do a lot of UDS using the EIA method with LCMS confirmation. Are you aware of anything OTC or Rx that can test positive for amphetamine/methamphetamine (strongly) on the LCMS? Patient does take a weight loss OTC thermogenic. Thanks for all of your help.

William MD

AskDocWeb: So far we have found nothing that would test positive for amphetamine/methamphetamine on a LCMS test. For those who are not familiar with the LCMS test, the abbreviation stands for liquid Chromatography/mass spectrometry. It is essentially the same as a GCMS confirmation test however LCMS testing is required for EtG testing for possible alcohol consumption. EtG is a metabolite of ethyl alcohol that is produced when the liver processes alcohol. It is a marker or indicator for recent alcohol exposure.

Subj: Testing for cocaine
Date: 12/17/2009
Can any of the following medications cause a postive testing for cocaine both in a hair strand and urine test:? Ciprofloxacn 500mg; Hyomax-Sl .125mg; Fluoxetine 20mg; Meloxicam 7.5mg; Loratadine 10mg; Premarin 1.25mg; Citalopram 20mg; Cyclobenzapr 10mg Thank you


AskDocWeb: Sorry Ralph, none of those drugs have been reported to show up as cocaine.

Subj: Full panel drug test
Date: 12/20/2009
I took 2 soma,1 percocet, 1 norco, and 5 vicodens on Friday and I stopped at about 10pm that night and I have a full panel drug test on Monday around 5 pm. Do u think I will be clean for all of them??? And what do somas, percocet, and vicodens show up as on a drug test?


AskDocWeb: Vicodin ES contains synthetic opiates and Percocet will test positive (not false) for opiates. As long as you have prescriptions for these drugs you should be okay.

Subj: I tested positive for opiates
Date: 12/20/2009
I took Vicks nyquil and dollar store cough syrup, and I am on Methadone, and have been clean 20 months and now I tested positive for opiates, which I didn’t use. It has really hurt me, and has made me question my own recovery? Could you tell me if this could be a false positive? Also I am in poor health, and I am on 10 different prescribed medications, so it could be a cross reaction too, right? please help! Thanks!!!


AskDocWeb: You can find all the products that (we have found references for) that have shown up as false positives on urine drug tests here.

Subj: Positive for THC
Date: 12/21/2009
My son tested positive for THC using a first check home test. He has been taking prednisone and Augmentin for walking pneumonia. He also takes 20mg of adderall daily. Could this cause a false positive?


AskDocWeb: Adderall is an amphetamine and has shown up as a positive for Meth (Ref: 2008 PDR, 18, 19) but not THC. None of the drugs you list have been reported to show a positive for THC.

Subj: Positive for cocaine
Date: 12/22/2009
I just took a drug test and it came up positive for cocaine. I have never used it. I have seen it, and maybe have came into contact with it, but not recently. The only meds I am taking is my albuterol inhaler(in particular its called ventolin HFA albuterol sulfate) and acetaminophen. I don’t understand how I can come up positive.


AskDocWeb: Sorry to hear about your positive test but neither of your meds is on the list for causing a false positive.

Subj: Tested positive for amphetamines
Date: 12/22/2009
I was recently hospitalized and tested positive for amphetamines. The only thing I was taking was Aldomet (methyldopa). The doctor in the hospital says I should not have been taking it. It’s an old medication that isn’t usually prescribed anymore.


AskDocWeb: While the use of Aldomet has declined it continues to have a role in difficult to treat hypertension such as the high blood pressure induced by pregnancy. We have seen one antidotal report of aldomet (methyldopa) showing up as a false positive for amphetamine at a clinic however, there is no documentation for a definitive answer to this yet.

Subj: Mine was stolen
Date: 12/25/2009
I may be drug screened for Opana 30 mg. I have none in my system as mine was stolen by a friend. Will the use of an antibiotic mess up a drug screen and cause Opana not to show? How can I get something like Opana in my system in 3 days? It is Oxymorphone and Morphine.


AskDocWeb: You can call the drugstore that filled your prescription and they will advise you as to how to go about getting a refill. They may need the number of the police report you filed in order to verify that the theft actually occurred.

Subj: Amoxicillin or metronidazole?
Date: 12/28/2009
Can u test positive on a antibiotic amoxicillin 500 mg or metronidazole 500mg? Please help.


AskDocWeb: There are several references that say Amoxicillin has shown up on urine drug tests as a false positive for cocaine (References 13, 16, 18, 20, 21, 26, and 29) but none for metronidazole. If you suspect your test result is a false positive then you can have it sent out to an outside lab for confirmation. This second test is called a Gas Chromatograph/Mass Spectrometer (GC/MS) test and can verify or deny the results of the first test.

According to Gateway Recovery Services and the Pathology Department of Borgess Hospital, Kalamazoo, MI (Reference 51), Metronidazole (ingested) can cause interference on EMIT assays that invalidates results.

Date: 12/29/2009
Dear Sir after spending most of my life abusing myself racing Motocross and having had over 9 trips into the OPERATING Room for mostly Ortho work 4 plates 27 screws not to mention double Hernia and spreenic absess. well in 98 I fell From the scafolding fracturing T-11 L-1 L-2 L-4 and herniating everything else it seemed I aquired a rather Pesky need for pain killers for many years leading up to the Shorting of a tiny line of what a friend said was “Great Painkiller” well turned out it truly was but it was Heroin so now after being clean since 2001 and in a sucseeful MMTP outpateint Clinic I get called in to the Office after have 6 yrs of clean everything for the People to wave in my face a paper that said I was taking something in the Family of something called “Benzos” where they Immediately took me down 30 Mgs and Took away my once a week privilegdes making me start all over again as if a Needle freak off the Street after having already transfered from another program o f over 3 yrs clean PLEASE TELL ME WHAT TO DO Gas Prices are as such that I drive 74 miles round trip 5 days a week Now ????


AskDocWeb: It is important to remember that a positive result on a urine drug test is only an indication of possible drug abuse. It is not proof and any positive result should be verified by a GC/MS confirmation test. If you are clean then check this list to see if you can find out what might be causing your false positive.

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