During the coronavirus disease 2019 (COVID-19) pandemic, the rapid expansion of diagnostic capacity prompted the Canadian Microbiology Proficiency Testing (CMPT) program to establish a new proficiency testing (PT) scheme dedicated to molecular and antigen-based identification of SARS-CoV-2. This initiative specifically targeted point-of-care testing (POCT) locations operating within the eight provincial Health Authorities of British Columbia (BC), Canada, with the primary objective of evaluating and maintaining testing quality. The PT framework involved 6 annual distributions, each comprising 4 samples categorized as either SARS-CoV-2–positive or negative. Program participation commenced with 23 sites in March 2021 and increased to more than 100 participants by December 2021. Evaluation of results from the first two survey rounds indicated that facilities using nucleic acid testing (NAT) consistently demonstrated satisfactory accuracy, whereas sites relying on rapid antigen detection (RAD) methods showed inferior performance, particularly when analyzing weakly positive specimens. Investigation into the causes of poor performance revealed shortcomings in both test execution and result interpretation, most often associated with inexperienced testers newly introduced to diagnostic workflows. Corrective actions included strengthened training and mentorship, comprehensive retraining of staff, revision of specimen handling instructions, and development of an instructional training video for participating sites. Following these interventions, overall accuracy improved, and RAD-based POCT site performance more closely aligned with that of NAT-based testing sites. Collectively, the PT program was highly effective and led to measurable improvements in diagnostic quality across the province. These findings highlight the indispensable contribution of external quality assessment (EQA) providers to patient safety and public health protection, particularly when testing is performed outside accredited laboratory environments.
