Background: Next-generation sequencing is a powerful technology that allows simultaneous analysis of several genes but also demands a well-designed quality management system owing to its complexity. We aimed to analyze the results of next-generation sequencing (NGS)-germline proficiency testing (PT) survey performed by the Korean Association of External Quality Assessment Service during 2017–2019 to assess the current status of the NGS-based genetic testing in Korea.
Methods: The recent 3-year results from the PT survey were investigated. During this period, PT survey was performed twice every year with two or three challenges per round. Correct results (%) were calculated from all tested regions; the trend by year and variation type was analyzed and the probable causes estimated.
Results: During this period, the number of participating laboratories increased from 5 to 22. The correct results were 97.2% in average and showed a gradual increase with year. The most common ‘unacceptable’ results were false-negative or false-positive, followed by inappropriate nomenclature and zygosity assignment.
Conclusions: The PT survey shows that the overall performance of NGS laboratories in Korea is highly confident, although some improvements may be needed. A method-based PT survey for the NGS test serves as a useful approach to assess the performance of NGS laboratories.

Keywords: Next-generation sequencing, Proficiency test, Method-based proficiency test