Quality Assurance and External Quality Assessment in Molecular Diagnostics: Standards, Challenges, and Best Practices for Clinical Laboratories

Quality assurance (QA) and external quality assessment (EQA) constitute fundamental pillars of molecular diagnostic testing, ensuring the accuracy, reliability, and clinical utility of diagnostic results. As molecular diagnostics increasingly become integral to infectious disease detection, oncology, and genetic testing, the need for robust quality management systems has become paramount. This review examines contemporary approaches to quality assurance and external quality assessment in molecular laboratories, with particular emphasis on international standards, reference measurement procedures, validation methodologies, and best practices for clinical implementation. Further to findings from Falak et al. study, they demonstrated that digital polymerase chain reaction (dPCR) can provide reproducible estimation of nucleic acid concentrations to support molecular external quality assessment panels, providing quantitative information for EQA schemes intended to support molecular testing [1]. Current frameworks including ISO 15189, ISO/IEC 17043, and CLSI guidelines establish requirements for participating laboratories and proficiency testing providers, yet significant challenges remain regarding standardization, analytical validation, and clinical interpretation. This review synthesizes evidence from recent peer-reviewed literature and international standards documentation to provide comprehensive guidance for molecular laboratory supervisors, medical laboratory technologists, and laboratory specialists on implementing and maintaining quality assurance programs. Key topics addressed include validation of molecular assays, external quality assessment participation, quality control procedures, management of molecular diagnostics stewardship, and monitoring of performance metrics. As demonstrated by the American Society for Microbiology Laboratory Practices Subcommittee, implementing structured diagnostic stewardship programs for infectious disease molecular testing significantly improves laboratory utilization patterns and patient outcomes [2]. The integration of comprehensive QA/EQA programs with clinical decision support systems and stewardship frameworks represents the current standard of practice in high-performing molecular laboratories.