Expert: Mark Eddy
Company: Fastest Labs
Phone: (502) 901-4560
Website: Louisville Drug, DNA & Alcohol Testing | Fastest Labs of East Louisville
Published on May 9th, 2025
My employee flagged on a drug test but claims they don’t do drugs. What should I do?
There are many reasons for an employee to flag on a drug screen. First, a drug screen is a rapid test that can flag for a multitude of reasons.
- The employee is ingesting drugs, knowingly or not.
People taking drugs can be extremely adept at hiding the truth. They may also be ingesting a substance that contains trace elements of THC unknowingly.
- A prescription medication.
Many prescriptions can cause this to happen. The most common is any ADHD medication. They will cause a positive flag for Amphetamines on most tests, depending on the dosage.
- An over-the-counter medication/energy drink/energy pill.
Due to lack of strict regulation and/or the way a rapid tests analysis, many substances can flag as a drug.
Rapid testing is quick, and inexpensive, but can produce some challenges. Because of this, our policy in all off the above cases is to send the sample off for further analysis at a certified testing laboratory. The more intensive testing process can eliminate most false positives. The sample is also sent to an MRO. This is a Medical Review Officer, a doctor specializing in drug testing. After analysis, they call the donor, if a valid prescription is provided, the test will be determined as a negative. That provides the employer with a Negative drug screen for their records, a win for all.
