What is a “false” positive, and how can they occur?
This is probably the most confusing issue regarding drug testing. Simply put, the tests are very accurate. If, during screening, they detect a drug, it is called a “presumed” positive. If the drug detected is one you are taking through prescription from your doctor, it is a negated positive. Some over-the-counter medications will test presumptive positive, but the confirmatory tests will rule out any illicit substances. What is generally called a “false” positive is simply a result which has not been confirmed.
This is probably the most confusing issue regarding drug testing. Simply put, the tests are very accurate. If during screening, they detect a drug, it is sent for confirmation through GC/MS. If the drug detected is caused by a prescription the donor is taking from doctor’s orders, it is a negated positive and reported as a verified negative. Some over-the-counter medications will screen positive, but the confirmation tests will rule out any illicit substances. What is generally called a “false” positive is simply a result which has not yet been confirmed.
