Use of Biosynthetic Controls as Performance Standards for Next-Generation Sequencing Assays of Somatic Tumors: A Multilaboratory Study Francine B. De Abreu, 1 Jason D. Peterson, 1 Sophie J. Deharvengt, 1 Robert Daber, 2 Vishal K. Sarsani, 3 Vanessa Spotlow, 3 Robin D. Harrington, 4 Chih-Jian Lih, 4 P. Mickey Williams, 4 Courtney H. Bouk, 4 Yves Konigshofer, 5 Catherine Huang, 5 Bharathi Anekella, 5 Lorn Davis, 5 Russell K. Garlick, 5 Andrea Ferreira-Gonzalez, 6 Catherine I. Dumur, 6 Helen Fernandes, 7 Stephen Haralampu, 8 and Gregory J. Tsongalis 1 * Background: Next-generation sequencing (NGS) assays are highly complex tests that can vary substantially in both their design and intended application. Despite their innumerous advantages, NGS assays present some unique challenges associated with the preanalytical process, library preparation, data analysis, and reporting. According to a number of professional laboratory organization, control materials should be included both during the analytical validation phase and in routine clinical use to guarantee highly accurate results. The Seraseq TM Solid Tumor Mutation Mix AF10 and AF20 control materials consist of 26 biosynthetic DNA constructs in a genomic DNA background, each containing a specific variant or mutation of interest and an internal quality marker at 2 distinct allelic frequencies of 10% and 20%, respectively. The goal of this interlaboratory study was to evaluate the Seraseq AF10 and AF20 control materials by verifying their performance as control materials and by evaluating their ability to measure quality metrics essential to a clinical test. Methods: Performance characteristics were assessed within and between 6 CLIA-accredited laboratories and 1 research laboratory. Results: Most laboratories detected all 26 mutations of interest; however, some discrepancies involving the internal quality markers were observed. Conclusion: This interlaboratory study showed that the Seraseq AF10 and AF20 control materials have high quality, stability, and genomic complexity in variant types that are well suited for assisting in NGS assay analytical validation and monitoring routine clinical applications. IMPACT STATEMENT This manuscript describes a multicenter study evaluating the use of synthetic control material as a quality control (QC) indicator in next-generation sequencing (NGS) assays. It is the first such study to test the perfor- mance metrics of various NGS assays and platforms using this QC material. The reproducibility of assays using this QC material in different laboratories with different operators helps assess the quality of NGS results being reported as part of precision medicine applications in oncology. The routine use of QC materials including different mutations will help ensure more standardized performance of NGS testing for guided therapy in patients with cancer. ARTICLES 138 JALM | 138 –149 | 02:02 | September 2017 ...............................................................................................................