Drug False Positive Test – How Your Employees Can Avoid It

Young scientist analyzing a chemical substance in a lab

More and more companies now opt for a drug and health screening to ensure that prospective employees don’t have any trace of drugs in their system. A positive test could have serious repercussions, including loss of job, fines, and even prosecutions. A false positive test could have the same outcome. How can you avoid a false positive on a drug test?

As an employer, you will want to require new employees to undergo a series of screenings and tests to ensure that the people you are hiring are who they claim to be and that you are aware of their background—previous convictions, drug use, etc. If an employee does happen to have a current habit of using illicit drugs, this can negatively impact their work, your business’s reputation, and could lead to further problems. 

Federal workplace guidelines do suggest that a drug test is carried out, and the most common tests include five different categories of drugs:

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

Depending on the drug or amount of a drug discovered through the screening, there are severe consequences that can arise. Additionally, many companies will emphasize that the consequences of not being willing to even take a test are just as serious as the consequences of receiving a positive test.

It is possible to get a false positive on a test, which could bring on the same serious consequences as a true positive. To avoid the difficulties that a false positive can bring on, your employees should do everything they can to prepare for their drug test. It is worth the effort to educate yourself and your employees before a drug screening to ensure that their results are valid.

Frequency of False Positives

It is important to know that, while the tests generally produce authentic results, any test could be inaccurate for a number of reasons. Minor lab errors and mistakes or the ingestion of certain foods or over the counter medications before being tested could contribute to some false positives. On average, drug screenings present a false-positive in 5-10% of cases and a false negative in 10-15% of cases, research shows.

If your employee is going to be screened for drug use, it could be beneficial to educate them about what triggers a false positive in order to avoid the negative repercussions of such results.

How to Avoid a False Positive on a Drug Test

Food and dietary supplements could affect a test and skew the results. Certain foods should be avoided before undergoing a screening. Large amounts of poppy seeds, hemp food products, ripe fruits, or foods that contain large amounts of yeast could contribute to a false positive. This list contains some common foods that could jeopardize a test and what drugs they can be mistaken for: 

  • Poppy seeds (Opiates or morphine)
  • Hemp food products (Marijuana) 
  • Hemp oil (Marijuana)
  • Yeast (Alcohol)

In addition to the foods mentioned, certain over-the-counter medicines could result in a positive test. Even if taken in small amounts, everyday pharmaceuticals like cold medicine, allergy medications, sleep aids, or nasal congestion can be mistaken for certain drugs. Here are some of the medicines to note:

  • Ibuprofen (Marijuana, barbiturates or benzodiazepines) 
  • Cold remedies (Amphetamines) 
  • Hay fever remedies (Amphetamines) 
  • Nasal decongestants (Amphetamines) 
  • Diet pills (Amphetamines)
  • Sleep aids (Barbiturates) 

All of the aforementioned food and drugs are harmless if ingested as intended and do not necessarily signal drug abuse—but if taken before a drug test, they can be mistaken for harmful drugs and give your employee a false positive. There are a few other common causes of false positives: 

  • Baby soap on skin
  • Incorrect testing methods 
  • Low drug test cut-off level—the level at which the concentration of a substance indicates a safety risk. If a cut-off level is low, even a hint of a substance could trigger a positive result.

The types of testing include urine, sweat, blood, saliva, and breath tests. Of the many kinds of screenings, blood tests and saliva tests tend to be the most accurate. False tests of course may be contested, so your employees should be aware of all the food and medications they consumed prior to the screening. A pharmacist may give written documentation to back this up, if the issue was medication related.

Overall, there are many factors to consider when a drug test is taken; causes of a potential false positive should be communicated to your employees to save them the time and worry of taking a test that won’t return accurate results.