What Can Cause A False Positive Drug Test?

Drug screening results can negatively affect many circumstances; therefore, accuracy is of the utmost importance. A worry for anyone undergoing drug testing – whether it be a urine, hair, saliva or blood test – is the possibility of a false positive result.

Drug tests are typically done on urine, but other types of specimens are becoming common, such as hair, saliva or blood. The most commonly screened substances, and also required by Federal workplace guidelines, include at least these five categories of drugs:

  • Amphetamines/methamphetamine
  • Cocaine
  • Marijuana/THC/Cannabinoids
  • Opiates/Heroin
  • Phencyclidine (PCP)

Drug tests generally produce false-positive results in 5% to 10% of cases and false negatives in 10% to 15% of cases. Sometimes, the food that we eat may affect the results of our drug tests as well as a few over-the-counter drugs that we take. Here are some of the most common things that may cause false positives in drug tests.

Cold remedies – Amphetamine

One of the core ingredients for cold medicine is pseudoephedrine, a synthetic amphetamine that is also used in making methamphetamine. Its action is to shrink the blood vessels along the nasal passages to aid in proper breathing when an individual has a cold. It is an effective drug to treat such condition, but if the individual undergoes drug testing while under medication, urine tests may show that he is positive for methamphetamine.

Antibiotics –¬†Opiates

Certain antibiotics, including rifampin and fluoroquinolones, can lead to false-positive results for opiates.

Antidepressants – Amphetamine

Many of the medications reported to cause false-positive results include a variety of antidepressants, which can be used for various indications. Of the selective serotonin reuptake inhibitors, sertraline has been reported to cause false-positive results for benzodiazepines and lysergic acid diethylamide (LSD) and fluoxetine has been reported to cause false-positive results for LSD and amphetamines.

Antipsychotics –¬†Amphetamine

In addition to antidepressants, many antipsychotic agents have also been reported to cause false-positive results.

Diet Pills – Amphetamine

Phenylpropanolamine, one of the main ingredients in most diet pills, can cause a positive drug test. Older diet pills that contain ephedra also can lead to a positive drug test.

Hemp Food Products – Marijuana

The ingestion of foods containing hemp, such as hemp-seed oil, have resulted in positive marijuana results.

Ibuprofen – Marijuana, Benzodiazepines

This is one of the most common over-the-counter drugs that people often take to quickly suppress pain. However, taking this painkiller a day before a drug test may result in a false positive test for benzodiazepines, marijuana or barbiturates.

Nasal Decongestants – Amphetamine

Common nasal decongestants (Dristan Nasal Spray, Neosynephren, Vicks Nasal Spray, Sudafed) can cause a positive reading for Amphetamines. They might ease breathing and provide relief from blocked nose caused due to cold and allergy; but it can make you test positive for Amphetamine and Methamphetamine.

Sleep Aids – Barbiturates

Many over the counter sleep aids may cause a false positive on a drug test for methadone, opiates, and PCP.

Poppy Seeds – Opiates/Morphine

You may be a fan of bagels with poppy seeds, but it might be best to skip eating this kind of food at least 3 days before a scheduled drug test. Poppy seeds, often found on bagels, rolls, and pastries have long been used as a defense against positive opiate test results encountered on a urine drug screen. It is known that poppy seeds do contain opiates – specifically morphine and codeine; however, content varies greatly depending upon seed source and processing. Food processing may lower the opiate levels in poppy seeds.

Tonic Water – Opiates

It was found out that tonic water, which is made from quinine, when consumed in large amounts may result in a false positive for opiates. Quinine water was used in the past to individuals who were afflicted with malaria. It was in the form of quinine water that these individuals were treated.

Baby Soaps and Shampoo

Exposure to trace amounts of baby soaps and shampoos, commonly stocked in grocery stores and pharmacies across the county, are leading newborn babies to test positive for THC, the active ingredient in marijuana. Products that led to the false positives included Johnson & Johnson’s Bedtime Bath, CVS Night-time Baby Bath, Aveeno Baby Soothing Relief Creamy Wash and Aveeno Baby Wash & Shampoo.

The impact of a false positive can have devastating results, it can lead to a termination from a job, missing out on an employment opportunity, or in the worst case even being arrested and incarcerated. With the millions of people subject to drug testing, 15% can have a significant impact on the lives of a huge part of our population. Before you take a drug test, you should research what medications or foods could result in a false positive.