What Can Cause a False Positive on a Drug Test?

Drug testing is becoming more popular nowadays than ever before, especially with medical marijuana being legal in 33 US states, in addition to the District of Columbia while recreational marijuana is now legal in 11 states. Pre-employment drug screenings are becoming a part of the job application process, as a condition of probation, and as part of random drug testing after employment. With that in mind, there are individuals who have not used illegal drugs who occasionally find themselves in hot water with a positive drug test.

In most cases, there are generally four types of drug screenings that an individual could be subjected to. They include the urine, saliva, hair, and blood test. All four of these test look for alcohol and detect commonly used drugs such as barbiturates, amphetamines, methamphetamines, benzodiazepines, cocaine, bath salts, diploids, opioids, heroin, codeine, MDMA, PCP, and cannabis.

So, What Can Cause a False Positive on a Drug Test for Different People?

There are many factors to consider scientifically and bio-chemistry wise when it comes to a false positive drug test. A false positive on a drug test can be caused by a laboratory identification mistake, foods you eat, liquids you drink, and your prescription medications. A common laboratory term for a drug test analysis is known as an immunoassay test. A positive result, in most cases, will trigger another test to be taken called the gas chromatography-mass spectrometry (GC-MS) test, which should reduce the odds of a false positive.

Foods That Cause False Positive Drug Test

Poppy Seeds
There’s nothing worse than receiving the news of a positive drug test, especially when you know you are clean. So, what can cause a false positive on a drug test from the foods you eat? Poppy seeds contained on bread or bagels can produce a positive result for opiates such as morphine and codeine.

Home-brewed poppy seed tea can even product lethal levels of morphine based on moderate use. Due to the extreme sensitivity of a drug test, the results of eating one bagel with poppy seeds the day before a drug test will produce a positive result for morphine or codeine; however, that bagel would not get you high. To avoid a false positive drug test from eating poppy seeds, it’s a good idea not to eat any for at least three days prior.

Pizza
There are a lot of people who would agree that pizza can be a drug all by itself. However, it’s not necessarily the pizza but the yeast contained in pizza and certain pastries that can cause a false positive on a breathalyzer test. According to breathalyzer manufacturer’s, yeast is utilized by fermenting sugars into certain substances such as alcohol, and if you’re pulled over in your car by a cop after consuming pizza, you can fail a breathalyzer test.

This also applies to certain fruit drinks and ripe fruits because they can ferment, which can produce enough alcohol to test positive for alcohol. Fortunately, detectable alcohol is in your mouth and not in your system. To avoid a false positive drug test from eating pizza, wait 15 minutes before you take the test and rinse your mouth out with water, and you’ll be fine.

Granola Bars
= Certain granola bars contain hemp seeds, hemp seed milk, and hemp seed oil. Eating granola bars containing hemp products can result in a positive drug test for THC, the psychoactive compound found in cannabis. Hemp is a cousin of the cannabis family; therefore, you should avoid eating granola bars for at least one week before a drug test.

Additionally, you should also be aware of vitamin B supplements, which also contain hemp seeds and certain tonic waters, especially the ones that contain quinine. Quinine comes from the cinchona tree’s bark.

Medications That Cause False Positive Drug Test

Whether you take a urine, saliva, blood, or hair drug test, these tests usually screen for illegal prescription medications as well. A false positive drug test can happen whether you’re applying for an internship, a job, or playing sports. Below is a false positive drug test list for prescription and over-the-counter medications that you should be aware of:

• Quetiapine (Seroquel): Quetiapine is a general antidepressant that’s used to treat schizophrenia, bipolar disorder, and depression. If you’re taking quetiapine, your drug test could turn up positive for methadone.
• Tramadol (Ultram): Tramadol is prescribed for pain. If you’re taking tramadol, you may test positive for PCP.
• Sertraline (Zoloft): Sertraline is prescribed to those who suffer from depression, and it’s an antidepressant. You could test positive for LSD or benzodiazepines if you’re taking sertraline.
• Amitriptyline (Amitril): Amitriptyline is also an antidepressant used to treat neuropathy (nerve pain), depression, and chronic pain. If you’re taking amitriptyline you could test positive for LSD.
• Doxylamine: Doxylamione is an over-the-counter drug such as Unisom. If you’re taking Unisom or other over-the-counter sleeping pills, you may test positive for PCP, opiates or methadone.
• Bupropion (Wellbutrin): Bupropion is prescribed for weight loss, smoking cessation, and depression. If you’re taking bupropion, you could test positive for LSD, amphetamine, and methamphetamine.
• Methylphenidate (Ritalin): Methylphenidate is well known for treating ADHD and for causing a false positive for LSD, amphetamine, and methamphetamine.
• Dextromethorphan (Delsym, Robitussin): Dextromethorphan is found in over-the-counter cough suppressants. You could test positive for PCP or opiates if you’re taking products containing Dextromethorphan.
• Labetalol (Trandate): Labetalol is used to treat high blood pressure. Labetalol can cause a positive test for amphetamine, methamphetamine, and LSD.
• Diltiazem (Cardizem): Diltiazem is also used to treat high blood pressure, and the same results as labetalol can occur.
• Diphenhydramine (Benadryl): Diphenhydramine is an antihistamine that can be found in many over-the-counter allergy medications. You could test positive for PCP or methadone if you’re taking products such as Benadryl, Advil PM, and Tylenol PM.
• Pseudoephedrine (Sudafed): Pseudoephedrine is used for nasal and sinus congestion. If you’re taking Sudafed, you can test positive for amphetamine or methamphetamine.
• Ibuprofen (Aleve, Naproxen, Advil, and Motrin): Ibuprofen is an anti-inflammatory that can be found in a lot of over-the-counter medications. Ibuprofen can cause a false positive for PCP, barbiturates, and THC.
• Metformin (Glucophage): Metformin is used for diabetes. If you’re a diabetic who is taking Metformin, you could test positive for amphetamine or methamphetamine.
• Trazodone and Fluoxetine (Prozac): Trazodone and Fluoxetine are both used to treat depression. If you’re taking medications such as Prozac, you could test positive for LSD, amphetamine, and methamphetamine.

Herbs That Cause False Positive Drug Test

Firstly, certain herbs can interfere with universal drug screening immunoassays. Secondly, as mentioned above, codeine and morphine are derived from poppy seeds, which can be found in poppy-seed cookies, pastries, bread, and bagels. Thirdly, the intake of just 1 teaspoon of poppy seeds or poppy-seed filling is enough to cause a false positive. Fourthly, other herbs like hemp are also known to cause a positive result for THC, especially hemp-seed oil. And lastly, herbal products containing ephedra can also cause a false positive test for methamphetamine.

The good news is that most herbs and herbal supplements such as Biloba, gingko, ginseng, green tea, cranberry, valerian, garlic, and St. John’s wort are less likely to cause a false positive drug test. Additionally, herbal drinks and teas also appear to be totally safe to use. Understanding the use of certain products that contain herbs that cause a false positive greatly reduces your risk of failing a universal drug screening.

Our Final Advice on What Can Cause a False Positive on a Drug Test

Armed yourself with the information that we provided above will help you make necessary adjustments before you take your drug test, so you can lower your risk of a false positive result. It can also help guide a conversation with your physician to make the necessary adjustments for alternative medications that will not cause a false positive on a drug test. If you received the news of a positive drug test, you have the right to request additional testing such as the GC-MS test mentioned above to confirm the authenticity of the universal drug screening immunoassay test. And next, you may want to consult our article about what to do if you have a false positive drug test.