Quantitative and Qualitative QC of Next-Generation Sequencing for Detecting Somatic Variants: An Example of Detecting Clonal Hematopoiesis of Indeterminate Potential

BACKGROUND: Because next-generation sequencing (NGS) for detecting somatic mutations has been adopted in clinical fields, both qualitative and quantitative QC of the somatic variants through whole coding regions detected by NGS is crucial. However, specific applications or guidelines, especially for quantitative QC, are currently insufficient. Our goal was to devise a practical approach for both quantitative and qualitative QC using an example of detecting clonal hematopoiesis of indeterminate potential (CHIP). METHODS: We applied the QC scheme using commercial reference materials and in-house QC materials (IQCM) composed of haplotype map and cancer cell lines for monitoring CHIP. RESULTS: This approach efficiently validated a customized CHIP NGS assay. Accuracy, analytical sensitivity, analytical specificity, qualitative precision (concordance), and limit of detection achieved were 99.87%, 98.53%, 100.00%, 100.00%, and 1.00%, respectively. The quantitative precision analysis also had a higher CV percentage at a lower alternative read depth (R2 = 0.749-0.858). Use of IQCM ensured more than 100- fold reduction in the cost per run compared with that achieved using commercial reference materials. CONCLUSION: Our approach determined the general analytical performance of NGS for detecting CHIP and recognized limitations such as lower precision at a lower level of variant burden. This approach could also be theoretically expanded to a general NGS assay for detecting somatic variants. Considering the reliable NGS results and cost-effectiveness, we propose the use of IQCM for QC of NGS assays at clinical laboratories.