Routine Mass Spec Urine Drug Testing Gaining Traction

More than half of urine samples from addiction treatment patients tested using mass spectrometry-based techniques show some level of unexpected drug use, according to a study published in the January/February issue of the Journal of Opioid Management. These results, the authors say, demonstrate the high number of cases of ongoing drug use or relapse missed by immunoassay urine drug testing (UDT). Immunoassay testing (IA) had its roots in point-of-care testing for forensic applications but was adopted in addiction treatment practice due to its quick, cheap nature. The tests are also limited due to their targeting of specific drug classes (i.e., amphetamines, barbiturates, benzodiazepines, and opiates). So, confirmatory testing with mass spectrometry-based tests are often necessary to verify the accuracy of IA results. Clinicians are increasingly recognizing the need for comprehensive, yet specific UDT, which is driving testing towards mass spectrometry (MS). Researchers from Millennium Research Institute (San Diego) analyzed 4,299 samples from the company’s laboratory database (Q1 2013) sent in from addiction treatment and recovery practices that consistently report medication lists to the laboratory. Samples all underwent liquid chromatography tandem MS (LC-MS). The vast majority of LC-MS results (92.6 percent) were positive for one or more substances. Less than half (48.5 percent) of the results were categorized as in full agreement with practice reports. The remaining 51.5 percent of samples fell into one of seven categories of unexpected results, with the most frequent being detection of an unreported prescription medication (n = 1,097; most often an amphetamine, tramadol, or an opiate) or detection of an unreported nonprescription medication (n = 1,097; most often cannabinoids and alcohol). Comparison IA and LC-MS results yielded the “most striking” results, the authors report. IA had a “high rate” of missing drug abuse, which the authors call “profound.” Specifically, the most actual positive results missed by IA were for amphetamines (43.9 percent, n = 112) followed by a 40 percent miss for barbiturates and cocaine (n = 34 and n = 38, respectively). False positive IA results were highest for phencyclidine (PCP; 100 percent of the 32 actual cases), 3,4-methylenedioxy-N-methylamphetamine (99.5 percent; n = 182) and tricyclic antidepressants (76.2 percent; n = 144). “Addiction treatment providers have borrowed not only a methodology of testing reflective of UDT’s forensic roots, but also a mindset. In forensic testing, only positive results are typically sent to the lab for confirmation,” writes co-author Steven D. Passik, Ph.D., explaining that confirmation is necessary because of the potential legal consequences. “Our results show that this confirmation of positives with LC-MS is often merited due to the limitations of IA methods. However, the confirmation of negatives has not historically been part of the quasiforensic use of UDT in addiction treatment and this seems to be in need of change.”
The Future of MS-Based Testing in Addiction Practice The authors acknowledge that the cost of IA and LC-MS testing can vary by 10fold, which raises questions regarding the financial impact of incorporating routine, nonconfirmatory MS testing into addiction treatment practice. The answer to this question, Passik says, requires a staged approach which will utilize more frequent testing to those who are newly sober (“to ritualize adherence” with a regimen that aids accountability) and less frequent testing in those demonstrating long-term sobriety. The American Society of Addiction Medicine December 2013 white paper recognized that drug testing technology “can and should” play a larger role in helping to deter unhealthy drug use, but the paper stopped short of making recommendations regarding testing frequency or strategy. Now, a consensus group of addiction professionals are drafting a forthcoming set of recommendations that are anticipated to address frequency of testing by suggesting a schedule of early IA sobriety testing three times a week, with one sample randomly sent to the laboratory for definitive (not confirmatory) LS-MS testing. Passik says these recommendations could represent a “pretty big” shift in testing once engrained in routine addiction treatment practice. Takeaway: There will be a noticeable shift in UDT towards MS-based tests for definitive, nonconfirmatory results. Use of this sensitive test will uncover lapses earlier in the addiction treatment process than IA.