False Positives with Non-FDA Approved Blood Testing

Blood Phosphatidylethanol (PEth) is a metabolite of alcohol that has an extended window of detection with a half-life of 2 - 14 days. A PEth test is a non-FDA-approved “Laboratory Developed Test” (LDT), used to determine if those monitored in an alcohol, or court ordered, prevention program have consumed alcohol over a 2 - 4-week period prior to the test. Despite experts testifying that it is impossible to receive a false positive, a growing number of individuals have claimed sobriety despite positive results. People have lost their careers, the custody of their children, and even their lives due to a positive PEth test result despite purported abstinence. The intent of this study was to assess the validity of the PEth test by determining if a positive test was possible even with an individual who abstained from alcohol consumption over a 30-day period. Ten out of 20 DBS blood tests, from the same blood for comparison, indicated excessive alcohol consumption despite abstinence, whereas ten DBS and 1 whole blood identified no consumption. The results of this research were conclusive that a false positive test can result without alcohol consumption, invalidating the validity of the PEth test. Additional research could identify the reasons false positives occur, including the many variables throughout the process from collection to storage and shipping, and lack of standard operating procedures at the lab, but also due to the variability in human genetics and physiology. However, the only purpose of this study was to determine if the test was valid by identifying if a false positive was possible without alcohol consumption. The resulting recommendation from this research includes a heightened awareness that false-positive blood PEth test results do occur, and caution should be observed in overreliance on this test as proof of alcohol consumption.