Dizon, Annabel

Context.— Accurate interpretation of drug test results is key to appropriate patient care in numerous settings, including pain management. Despite recommendations that providers should consult laboratory professionals for guidance when necessary, literature demonstrating laboratorian expertise in drug test interpretation is lacking. Objective.— To evaluate participating laboratories’ performance on the case-based, interpretive (“dry”) challenge included with each Drug Monitoring for Pain Management proficiency testing program from 2012–2023. Design.— All challenges (n = 23) required participants to identify if drug test results were consistent or inconsistent with prescribed medications in the case history. Relevant medications, presumptive and confirmatory drug test results, and participant responses were extracted from program summary reports and examined for performance and common themes. Results.— Overall, 91.8% (6821 of 7431) of participant responses correctly identified whether drug testing was consistent with medications. There were 8 challenges with participant scores less than 91.8% (range, 59.8% [49 of 82 responses] to 88.9% [193 of 217 responses]). Common knowledge gaps identified in these challenges included false-positive presumptive (screening) results, minor metabolism of opiates, and recognizing that presence of a nonprescribed drug is inconsistent with prescribed medications. Although some participants repeatedly responded incorrectly, there were no associations between laboratory type, personnel responding, or analytical performance and incorrect responses to interpretative challenges. Conclusions.— Program participants performed well overall, but several concerning educational gaps were identified. Laboratorians have a role in providing interpretative guidance for drug testing and should emphasize ongoing education to ensure competence in the setting of constantly changing prescribed and nonprescribed drug use.

Context.— Consequences related to nicotine (NIC) use remain a major health concern, leading to demand for testing to detect NIC, metabolites such as cotinine (COT), and related tobacco alkaloids, including anabasine (ANAB). NIC-related testing is not standardized among laboratories, nor are there clinical or regulatory guidelines to inform decisions such as appropriate screening cutoffs or limits of quantitation. Objective.— To evaluate analytical performance and reporting practices of laboratories that perform NIC-related testing by reviewing participant responses to the Nicotine and Tobacco Alkaloid (NTA) Proficiency Testing Survey. Design.— NTA results were retrieved from 2017 (the first year of the survey) through 2020. Survey participants, methodologies, and results were evaluated for all analytes, and simulated grading was performed for COT. Additional data, including limits of quantitation, qualitative cutoffs, and reasons for testing, were reviewed. Results.— Participant growth was steady for qualitative COT testing. Participation was stable for NIC, ANAB, and quantitative COT testing. Overall, participants performed well on survey challenges. However, reporting thresholds were widely divergent, ranging from 10 to 3000 ng/mL and 0.5 to 300 ng/mL, respectively, for qualitative and quantitative COT testing. Screening cutoffs were as high as 100 ng/mL for ANAB and 1000 ng/mL for NIC. Conclusions.— Although participating laboratories performed well on the NTA Survey, the wide diversity of qualitative and quantitative reporting thresholds creates substantial risk for misinterpretation of results, and could lead to analytical concerns such as excessively high false-negative or false-positive rates. NIC-related testing would benefit from evidence-based guidelines to drive standardization of reporting.

Context.— Clinical and forensic testing for ethanol biomarkers, including ethyl glucuronide (EtG) and ethyl sulfate (EtS), is used to discern alcohol use from abstinence. These markers can be key in major decisions, including transplant eligibility or retaining licensure after alcohol misuse. Accuracy, precision, and recognition of the implications of reporting cutoffs are all essential for correct interpretation. Objective.— To evaluate trends in testing for EtG and EtS, including how laboratories perform testing and how comparable participant results are. Design.— The study examined the College of American Pathologists ethanol biomarker proficiency testing survey from 2013 to 2019. Trends in methodology, reporting cutoffs, and participant performance were evaluated for qualitative and quantitative EtG testing and for quantitative EtS testing. Results.— There was little consensus in reporting cutoffs, which ranged from 10 to 1000 ng/mL for EtG and 10 to 1500 ng/mL for EtS. Although median EtG and EtS compared well with target concentrations, individual participants' results varied widely. For quantitative enzyme immunoassay, accuracy and precision were best in EtG challenges less than 1500 ng/mL. For EtG or EtS by mass spectrometry, overall accuracy was good over a wide concentration range, but variability between participants was high. Approximately 10% (409 of 4059) of results were unacceptable, which for mass spectrometry corresponded to more than 35% above or below the group mean. Conclusions.— Although many participants performed well, there was insufficient consensus in reporting cutoffs, and a consistent fraction of laboratories failed to achieve survey standards. Guidelines for assay performance and reporting could greatly benefit laboratories and end users.