Comparison of Measurable Residual Disease in Pediatric B-Lymphoblastic Leukemia Using Multiparametric Flow Cytometry and Next-Generation Sequencing

Measurable residual disease (MRD) testing, a standard procedure in B-lymphoblastic leukemia (B-ALL) diagnostics, is assessed using multiparametric flow cytometry (MFC) and next-generation sequencing (NGS) analysis of immunoglobulin gene rearrangements. We evaluated the concordance between eight-color, two-tube MFC-MRD the LymphoTrack NGS-MRD assays using 139 follow-up samples from 54 pediatric patients with B-ALL. We also assessed the effect of hemodilution in MFC-MRD assays. The MRD-concordance rate was 79.9% (N=111), with 25 (18.0%) and 3 (2.2%) samples testing positive only by NGS-MRD (MFC NGS MRD) and MFC-MRD (MFC NGS MRD), respectively. We found a significant correlation in MRD values from total nucleated cells between the two methods (r=0.736 [0.647-0.806],