False Positive Drug Test: Blame Your Food and Medications

False Positive Drug Test Why Does It Happen

Strangely enough, common food items or medications might be the reason you had a false positive drug test. Discover in detail about who are the real culprits.

Firstly, a false positive drug test can be a devastating news for you, your family members and friends. Furthermore, It can take its toll on your professional and social life as well. Therefore, learning about its causes will help you take necessary precautions before you finally go for a drug test.

You may need to have drug abuse tests at your college, workplace or to fulfill certain legal requirements. Usually, these tests analyze the urine sample. However, the doctor may ask for other specimens like saliva, hair or blood.

Drug abuse tests detect the presence of amphetamines, cannabinoids, cocaine, heroin and phencyclidine in the specimens. Regrettably, no drug test can have 100% accuracy. As a result, you might end up having a positive result for drugs you did not take.

In addition, a number of food items and some prescription or OTC medicines can also turn the test results against you.

What is A False Positive Drug Test?

A false positive drug test means you get a positive result for the drug but in reality, you didn’t take it.

You might be wondering how it is possible for to test positive if you haven’t taken any drugs.

However, it’s quite possible. And studies suggest false positive test results occur in 5 to 10% of the total cases.

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How Does False Positive Drug Test Occur?

Drug Test

False positives occur when the analytical drug detection method recognizes some of the molecules in your body as drugs. Due to some errors in the analysis, it fails to differentiate between the drug molecule and other structurally similar molecules. Consequently, after a positive test, you will need other tests to confirm abuse of the drug.

A drug test commonly involves the use of Enzyme-mediated Immunoassay (EIA). Because this test offers the privilege of mass screenings, quick results and low cost. As a result, most doctors prefer EIA. However, this test is not error-free and can lead to false positive results.

EIA uses a complex of enzymes and antigens. In addition, the test results depend on whether the drug or the antigen binds to the antibody present in the body.

Even if you have a very small quantity of the drug in the body, it binds to the antibody leaving the enzyme free. Next, the free enzyme produces certain signals which are detected by an instrument called spectrometer.

If there are no drugs, the antigen binds to the antibody in the enzyme-antigen complex thus limiting the activity of the enzyme. Consequently, the limited enzyme activity means the spectrometer cannot measure the signals.

Firstly, false positive drug test can occur due to a mismatch between the antibody and the substance. This could be chemically related to the drug or its metabolites. Sometimes, you might eat something without realizing that they contain trace amounts of the drug or related substances. For example, bagels, rolls, and pastries contain certain amounts of poppy seeds that may give a false positive result for morphine.

In any case, when EIA shows positive, you’ll need to confirm it using a more advanced technique called GC-MS. (Gas chromatography Mass Spectroscopy)

What Can Cause A False Positive Drug Test

incidentally, certain medications, both prescription and OTC, can cause a false positive drug test. It is because many of the constituents in these medications might be chemically similar to the drugs being tested.

Here are some medications which might give a false positive result

  • Quinolones: Antibiotics such as ofloxacin, gatifloxacin, and ciprofloxacin can give positive test results for opiates and phencyclidine.
  • Rifampin: This first line antitubercular medication might be the cause for the positive opiate test.
  • Verapamil: Verapamil is an antihypertensive medication that may cause positive methadone test in some cases.
  • Diphenhydramine: Antiallergic medication diphenhydramine may trigger positive results for methadone, opiates, and phencyclidine.
  • Antidepressants: Sertraline may show positive results for diazepam.
  • Analgesics: These include common OTC pain medications like ibuprofen and naproxen.
  • Certain OTC products such as anti-cold tablets that contain pseudoephedrine could be the reason why you tested positive for amphetamines.

Note: This list does not contain all the medications that might cause a false positive drug test. Therefore, it’s important you tell your doctor about all the drugs (prescription or OTC), supplements, and food items.

Factors That may Cause False Positive Drug Test

  • When did you have the test
  • If there are metabolic products of the actual drug in the body
  • Sensitivity of the detection technique

The Bottomline

In conclusion, a false positive drug test does not mean you abuse drugs. It means you need to recheck your diet or medication. In any case, if the test is positive, the patient should consult the doctor and take another test to confirm.

You can learn more about the false positive drug test, drug addiction or aspects of drug abuse or other tests. First, talk to the experts near you or click here for more details.

False Positive Drug Test: Blame Your Food and Medications

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Comments 16

  • I have a question maybe someone can direct me where and what to do. I am on some heavy pain meds due to two horrific neck surgeries for the past 15 years. During that 15 years I was drug tested regulary with urine drug test where there was never a problem. On Wednesday September 5th my pain clinic Dr in pa did the first oral drug test I have ever done in my 60 years of life. 5 days later they call me telling me that they are discharging me because my oral drug test tested positive for cocain and suboxone, I dropped the phone because I have never done these drugs in my life .. Plus he put this false positive in my records and now no Dr will see me. In my.neck there is 3 inches of bone from my left leg, two inches of hip bone, two 10 inch bolts and 16 screws I have 5 days of medication left im lost !!!!

    • Primary care may help but most say go to pain clinic. Won’t the place that discharged you do another test. Yesterday I was at probation and they drug tested me and alcohol tested me and alcohol came back with a faint line. I passed however my probation officer is suspicious. The last drug test before that had a faint line for subsoxone. I passed however I’m afraid every time they will violate me due to these tests. I’m in a lot of pain due to a car accident and on disability and no one will give me pain mess unless I have surgery. I was discharged from a subsoxone clinic a few years ago due to a positive test. They should know these tests aren’t a 100% accurate. They drug tested me in hospital and came back positive for pop which I’ve never touched. We did research and I was on a anti depressant called Effexor which caused the positive reading for pop. I know what your going through if that any consultation. I hope something happens for you. I know it’s a tough spot. Don’t know if I was any help.

    • You have the right to insist on a more exotic screening. Blood, hair, etc.
      If you have nothing to hide, hold your head up high and march in there and insist upon another type of test or outside third party testing.
      The same thing happened to me with meth! Never in my life! I demanded another test and passed it with flying colors.

    • It might be to late now but demand they retest. I failed a drug test for cocaine because of amoxicillin. If you’re taking tramadol, non narcotic pain meds that can test positive for suboxone.
      Most places normally do the cheap test, I demanded a retest for the expensive one and I was cleared.
      Hope you were able to fix this, good luck!

      • What milligram was the amoxicillin that you took that showed a positive for cocaine ain and was it a urine test that they sent to a lab?

    • I just had the exact thing happen to me. Go to your regular doc and tell them what happen and have them order a hair test. If that comes back positive then there is something in your body causing it. It’s your docs job to find out why. Sometimes the reason is not good news. Good luck

  • My son and daughter in law have been required to random mouth swaps. Where they live their 2 children are in state custody. The organization requires then drug testing with mouth swabs. In the 10 months the children I have not tested positive for drugs or alcohol. On November 5th 2018 my son tested positive for drugs and alcohol. This 1 positive test may jeopardize their children coming home by Christmas. What advise can I give them to prove the test is a false positive?

  • I am on D.O.C. & I have to be tested for drugs & alcohol & they use a mouth swab on me. I got a false positive for methamphetamine! I also go to a methadone clinic everyday & they U.A. me randomly all the time too! When I got the false positive at D.O.C. my doctor at the clinic checked for me & then wrote a letter to my probation officer telling him that I had did a u.a. with in a couple of days of days of the one I did for D.O.C. my doctor then checked out the meds. I was on & wrote another letter to my probation officer telling him that the stomach meds. I was on (Zantac!) Can cause a false positive for amphetamines & methamphamines! I have been clean off drugs & alcohol since July 3rd. 2018!!! I am very proud of myself & so are the everyone at the clinic I go to everyday!!! I take my sobriety very seriously & love being off drugs!!! !!! I gave my probation officer the letters my doctor sent & they told me that the letters didn’t matter!!! If The test comes up positive I go to jail!!! So I went to jail!!! I feel really bad for you!!! The only thing I can tell you is to tell your kids to tell them that they will go to treatment. It’s probably the only chance they have! It’s only 28 days so I would think there kids are worth that of course!

  • Hello, I was recently dismissed from my primary care physician for a dip test that came back positive for PCP! Are you kidding me? I’ve never even considered doing drugs, let alone PCP for cripe sakes! The office sent me a letter stating that I tested positive for three different drugs. Two of which they prescribed to me. I demanded a retest and was denied, flat out! I offered to take a gas chromatography hair test at my cost, and was denied again. Come to your find out that two of the meds that THEY prescribed to me can cause the false positive. Needless to say I am very furious that this is a permanent scar on my medical records and I have filed an official complaint against this doctor. Their own Lab told me that that test should have been sent out to another Lab for a confirmation test. Mind you they still had the original urine sample for 7 days. This doctor is so arrogant that he doesn’t want to be proven wrong. I think that if the word got out of the circumstances that he would look bad or have to stop bragging about all the people that he dismisses from the practice for failed drug tests. I am still going to have the hair sample test done and provide the results”false or positive”! I find it ridiculous that in the eyes of the doctor that there is no way that they could have been mistaken. There are unfortunately, I have found no legal course of action for those of us who are victims of these mistaken arrogant Health care “PROFESSIONALS. This is just wrong.

  • I havd to take tests for dss randomly.. Ive done failed three tests now.. I take two tests each time.. Only one of them are negative.. What they said i failed for I know for a fact I havent used or do.. I take several other drug test for other places my doc ect and theyve came back negative.. Ive looked at the cutoff and the tests and ive seen the second test is at the cutoff and the levels came way down from the first one.. My dss worker is only reading it stating positive not looking at the cutoff or the levels.. Seeing that they would be negative from the second test.. Idk how the tests are coming back positive and its only been a few with the exception that one is positive and one is negative.. But all thw others are negative.. Idk what to do.. My kids are at stake.. I KNOW FOR A FACT THAT I DONT USE BUT I KEEP GETTING FALSE POSITIVE SCREENS.. ANY SUGGESTIONS..

    • I need to know that roo. I passed pee and blood test but hakr test was a issue but i have used in past years ago. T
      I know i havent used in tbe ladt 2 years. But my so called caseworker is counting it as a positive drug screen. Someone please tell me what i can do about it so my baby doesn’t get taken

  • My drug test came back positive for meth on a mouth swab test & I haven’t done any meth.
    I had a cold over the holidays & taken cold medicine. I also have seizures. I take trazodone, hydroxyzine. What happened? Is this possible?

  • I tested dirty for ampetamine I had used Vick’s vapor pen for my cold. Sure enough I looked it up and I became a victim I’m on federal probation a lot of cold meds will come positive

  • Start off saying glad i read this gives me some kinda answers but me and my husband recently found out we were pregnant i take suboxone 8mg strip daily i went to hospital with stomach pain and admitted i had a drug screen come back positive for meth which i have not used been around or know anyone who uses, being told this i realized this wasnt the first time this has happened i have been taking cold medicine this time but last time only suboxone i drug test regularly at my suboxone dr and never have this issue other drs drug tests are coming up positive havent a clue why…

  • Can requip cause a false positive

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