Operationalizing Quality Assurance and Navigating Complex Diagnostics in Multiplex Testing
Casting a wider net catches more fish, but it also drags up things you weren’t looking for. Multiplex panel testing can work in the same way, depending on a clinical laboratory’s context and needs. In our September 2024 article, A Closer Look at Multiplex Panel Testing, we explored how testing for multiple targets at once changed infectious disease diagnostics. We also looked at the challenges of using them, such as high costs and the risk of false positives when diseases are rare. Now that laboratories are running these larger panels more often, the focus has shifted from setting up the technology to maintaining long-term quality. To make sure these complex tests give doctors clear, reliable answers instead of confusing background noise, labs need strong proficiency testing and careful panel management.
The risk of false positives and unexpected cross-reactivity remains a critical concern for laboratory quality managers, particularly within large respiratory or gastrointestinal panels. Research evaluating molecular multiplex performance emphasizes that as panel targets increase, the potential for non-specific amplification and background interference grows proportionally [1]. Routine participation in external proficiency testing programs provides laboratories with impartial, peer-compared data to detect subtle calibration shifts or reagent lot variability before these issues impact patient management [2]. “Routine proficiency testing gives bench techs a structured opportunity to practice and reinforce proper workflow,” explains Laura Schreiber, Proficiency Testing Coordinator at WSLH PT. Schreiber emphasizes that because a positive multiplex result indicates the detection of nucleic acid rather than a definitive clinical diagnosis, mitigating contamination risks is vital.
“When a lab has a failure in a PT challenge, it often highlights small lapses in pre-analytical handling, pipetting technique, reagent management, or contamination control,” Schreiber notes. “Identifying these issues in a controlled setting allows the team to correct them before they affect patient care.”
Beyond individual patient outcomes, strict quality control directly impacts broader public health surveillance. Clinical laboratories contribute vital aggregate data to regional and national surveillance platforms like the National Respiratory and Enteric Virus Surveillance System. The CDC notes that NREVSS plays an essential role in describing the temporal and geographic circulation patterns of these viruses, which helps public health officials monitor changes in typical annual trends and identify emerging outbreaks [3]. At the state level, collaboration is equally critical to managing the background noise of multiplex testing. Allen Bateman from the Communicable Disease Division at the Wisconsin State Laboratory of Hygiene notes that their team takes a comprehensive approach by requesting both data and physical specimens from clinical laboratories as part of their Laboratory-Based Surveillance Plan.
“The data informs overall transmission levels and pathogen seasonality,” Bateman explains. Furthermore, this physical specimen sharing directly addresses the challenges of expansive syndromic testing. “For specimens, we perform confirmatory testing and comprehensive characterization of the pathogens, which helps us to identify trends in false-positivity of certain syndromic panels,” he adds. Maintaining high analytical specificity ensures this surveillance data remains trustworthy, underscoring the vital public health role of continuous proficiency monitoring.
Modern test utilization initiatives also require laboratories to evaluate their multiplex offerings regularly, balancing targeted, small-panel assays for outpatient settings against comprehensive panels for inpatients. Aligning panel selection with stewardship guidelines supported by the American Society for Clinical Pathology (ASCP) requires ongoing review of laboratory performance and provider ordering habits [4]. Comprehensive proficiency testing documentation supports these stewardship efforts by validating that selected panel configurations perform consistently across diverse patient populations and clinical contexts [4].
As multiplex testing methodologies continue to evolve, WSLH Proficiency Testing remains committed to assisting clinical laboratories with contextually relevant and comprehensive testing options. By pairing rigorous proficiency challenges with peer-comparative evaluations, laboratory leaders can confidently navigate complex multiplex data, ensure diagnostic precision, and uphold the highest standards of patient care and public health safety. Do you have questions about multiplex testing proficiency testing? Contact our team of technical experts for assistance at ptservice@slh.wisc.edu, or by calling (800) 462-5261.
References
[1] Ramanan, P., Bryson, A. L., Binnicker, M. J., Pritt, B. S., & Patel, R. (2018). Syndromic Panel-Based Testing in Clinical Microbiology. Clinical Microbiology Reviews, 31(1), e00024-17. https://doi.org/10.1128/cmr.00024-17
[2] Wallace, P., & McCulloch, E. (2021). Quality Assurance in the Clinical Virology Laboratory. Encyclopedia of Virology, 64–81. https://doi.org/10.1016/b978-0-12-814515-9.00132-6
[3] Centers for Disease Control and Prevention. (2024). The National Respiratory and Enteric Virus Surveillance System (NREVSS). U.S. Department of Health & Human Services. https://www.cdc.gov/nrevss/php/dashboard/index.html
[4] American Society for Clinical Pathology. (2024, February 6). ASCP Transitions Choosing Wisely Program, Continues Commitment to Effective Test Utilization. ASCP News. https://www.ascp.org/news/news-details/2024/02/06/ascp-transitions-choosing-wisely-program-continues-commitment-to-effective-test-utilization
