A Pharmacist-Led Process to Monitor Discrepant Urine Drug Screen Results
Background: A urine drug screen (UDS) is a common risk-mitigation strategy tool for prescribing controlled substances, particularly opioids. Due to their complexity, UDS results can be misinterpreted and thereby have profound impacts on the patient-clinician relationship. From 2021 to 2022, a clinical dashboard to review potentially discrepant UDS results—based on a comparison of the results to the patient’s medication list—was made available by the Veterans Health Administration.
Methods: This quality improvement project implemented a process for weekly clinical pharmacist reviews of the UDS dashboard. Significant discrepant UDS results were reviewed in depth. From June 2022 through September 2022, 700 UDSs were performed and 60 patients had significant discrepancies that warranted in-depth review.
Results: Pharmacist interventions during the review included 39 collaborations with medication prescribers to discuss follow up (65%), 25 queries to a prescription drug monitoring program (42%), and 9 confirmatory UDS on the original sample (15%). In-depth reviews were required for about 4 patients weekly, with a mean length of 14 minutes.
Conclusions: A pharmacist-led process to monitor discrepant UDS results led to opportunities for collaboration with prescribers and positively impacted confirmatory testing at a rural veterans affairs health system.
Discussion
Findings of this project illustrate that the use of a clinical pharmacist to monitor a dashboard of discrepant UDS results created opportunities for collaboration with clinicians and impacted confirmatory testing and PDMP monitoring practices.
At the local level, the process had numerous benefits. First, it was a reasonable amount of workload to generate pharmacist interventions: the PMOP coordinator conducted an average of 4 in-depth reviews weekly, each lasting about 14 minutes. Thus, the UDS dashboard allowed the PMOP coordinator to actively surveil all incoming UDS results for potential discrepancies in about 1 hour each week. Pairing the automation of the UDS dashboard with the clinical judgment of the PMOP coordinator seemed to maximize efficiency. VABHHCS provides primary and secondary medical and surgical care to a rural population of approximately 20,000 patients across 5 states; the time required at facilities that serve a higher volume of patients may be greater.
Second, the project served as an opportunity for the PMOP coordinator to provide case-specific clinician education on UDS monitoring. As medication experts, pharmacists can apply their medication-related knowledge to UDS interpretation. This includes understanding drug metabolism and classification and how they apply to UDS results, as well as recognizing medication therapies that could contribute to false-positive UDS results. Research suggests that clinicians may have gaps in their knowledge and may welcome pharmacist assistance in interpreting UDS results.7,8
Third, the project helped improve rates of confirmatory testing for those with unexpected positive UDS results. Confirmatory testing should be strongly considered if positive results would have significant implications on the future course of treatment.4 The PMOP coordinator ordered a confirmatory test on 9 patients using the same urine sample used to conduct the initial UDS, minimizing the burden on the patient and laboratory staff. Confirmatory testing was limited by the laboratory’s sample retention period; if the need for confirmatory testing was not recognized soon enough, the sample would no longer be available for retesting. Health systems may consider the use of reflexive confirmatory testing with UDS as an alternative approach, although this may come at an additional cost and may not be warranted in many cases (eg, only 39.7% of all potential discrepancies were deemed as significant within our project).
There were notable incidental findings in our quality improvement project. Among patients with a significant discrepancy on UDS, 50% had a history of ≥ 1 discrepant UDS result. This further emphasizes the importance of appropriate use and interpretation of UDS monitoring for all clinicians, as this may prevent prolonged and potentially inappropriate treatment regimens. Secondly, rates of mental health diagnoses among those with a significant UDS discrepancy seemed relatively high compared to population-level data. For example, among veterans, the overall lifetime prevalence of posttraumatic stress disorder is estimated to be 8.0%; in our project, 35% of patients with a significant UDS discrepancy had a posttraumatic stress disorder diagnosis.17 This relationship may be an area of further study.
Lastly, it was surprising that the overall rates of UDS and PDMP checks within the past year were 56% and 65%, respectively. VABHHCS requires veterans on controlled substances to have these risk-mitigation strategies performed annually, so our suspicion is that many were falling out due to having been most recently evaluated 12 to 16 months prior. This may represent a limitation of our data-collection method, which reviewed only the previous 12 months.
