It is possible for an initial drug screen to lead to a false positive result. Studies suggest that 5-10 percent of drug tests may be false positives, while 10-15 percent may be false negatives.1 However, proper confirmation testing can confirm the presence of illicit drugs or sometimes even identify the cause of false test results. Before you start a long quest to determine what caused your false positive drug test read the following information. 

Clearly, inaccurate drug tests can and do happen, sometimes with devastating results for the person being tested. What causes a drug test to lead to a false positive, and how can we avoid the serious life consequences of false positive drug tests?

The Impact of False Positive Drug Test Results

Employers supporting a drug-free workplace and public agencies usually employ an urine drug test or immunoassay tests as a quick and cost-effective way to complete their drug testing requirements. These types of tests are screening drug tests, and are prone to false positive  results when not performed along with confirmation testing. 

Unless they are followed up with confirmatory testing such as gas chromatography mass spectrometry (GCMS), these false results can have serious consequences like these:

• Receiving a false positive for cocaine, opioids, or meth can result in immediate job loss or prevent someone from being hired.
  Receiving a false positive for probation could result in loss of privileges or incarceration for someone on parole or probation.
• Receiving a false positive for CPS could result in losing custody of a child or failing to regain custody when a parent is in recovery.
• Students may be excluded from competitive sports, be suspended, or expelled from school after a false positive result on a drug test.
• Patients might receive inappropriate medical care or be excluded from pain management programs based on perceived drug use.

What Causes False Positive Tests?

Ingesting or coming into contact with a drug can possibly trigger a drug test and can lead to false positive results. In some cases second-hand or incidental contact with an illicit drug can trigger a false positive on a urine drug screen. To be clear, if you have been exposed to a drug, or have had “passive exposure” to a drug or inhalant of that drug the test is not actually a false positive but instead is in fact identifying the drug. Avoiding these common causes will reduce your chances of dealing with a false positive drug test:2

• Secondhand contact. If you share a home or spend time with someone who smokes pot or other drugs, such as “meth” or “crystal meth” or “crack cocaine” you will inhale smoke or other fumes, which might show up on a drug test as low level use. It is not common, but also not impossible for an individual and even a child to test positive for crystal meth simply from living with a person that smokes the drug and you later touching surfaces in your environment. (for passive exposure testing consider a ChildGuard environmental exposure test) 
• Poppy or hemp seeds. Eating poppy seeds or hemp seeds can cause a false positive on a drug test. These seeds have small traces of opium or cannabis oils, which an initial test detects as drug use in some cases. While a good quality drug test should not result in a true false positive in this case there are some very low cost, lesser quality drug tests sometimes being used. Follow-up drug testing by GCMS technology should eliminate this occurrence. 
• Prescription medications. Some of our clients are so concerned they may get a false drug test result due to their prescription that they simply stop taking their prescriptions. This of course is not a good idea to stop taking a prescription that your doctor has deemed necessary. Realize any reputable drug testing agency should provide medical review for what we call “non-negative” drug test results. Medical review is the process of establishing and verifying that the prescription is in fact causing the positive drug test. If so, the report will be notated appropriately! At AMH Nationwide this service is part of our process and our price! This is especially important with pre employment drug testing simply because an employee should not be required to discuss their private prescriptions with their employer! Also, do not bring your prescription to the lab with you, we will call only if we need to discuss your prescription. 
• Mouthwash and hand sanitizer. Using either of these products on a regular basis can cause a false positive for alcohol. Especially in the transportation industry, failing a random urine test for alcohol can ground a pilot or put a bus driver on the bench. Being falsely accused of drinking on the job can get a construction worker or warehouse employee fired on the spot. However, before you get too concerned about this realize there is a wide variety of alcohol tests. This situation can occur with some alcohol tests, but not most! 

Interpreting and Confirming Drug Test Results

While the initial immunoassay test is helpful for large-scale screenings at low cost, when a positive result is obtained, the patient or employee is entitled to a more accurate test to confirm the results and eliminate the possibility of a false positive. If collection and testing have retained a portion of the sample for confirmatory testing, this should be done with a more accurate testing method.

The remaining urine may be used, although a more accurate result spanning a longer period of time can be obtained by switching to hair or nail analysis. Confirming tests should use gas chromatography-mass spectrometry (GC-MS) or high performance liquid chromatography (HPLC) and be performed by a professional and impartial laboratory. These methods of testing reduce the chance of a false positive to almost zero.

Choosing a Reputable Drug Testing Provider

Performing strip tests onsite is likely to generate more questionable test results and a complete inability to follow up with more accurate testing methods when a positive result is obtained. Employers and government agencies can provide more accurate tests performed by impartial and professional technicians by switching to a trusted testing provider like AMH Nationwide.

We offer accurate testing of urine, hair, and nails with automatic confirmation of all positive test results. Negative results are available quickly, and positive results reported only when they have been confirmed with more advanced testing methods. AMH handles drug testing for employers and agencies across the country with fast and accurate testing through Quest Diagnostics, LabCorp, and other industry leaders.

Let us find the right balance of price and testing technology for your needs with our certified testing labs in full compliance with local, state, and federal regulations. In most cases, advanced confirmation testing is included in our prices, so even if your lunchroom serves poppy seed bagels every day, you can accurately assess your employees and take appropriate actions with confidence. Contact us today to start accurately testing tomorrow.

Sources:

1. https://www.drugs.com/article/false-positive-drug-tests.html
2. https://www.webmd.com/drug-medication/ss/slideshow-drugs-false-positive-test