Evaluation of MRD Testing in B-ALL

The standard-of-care for monitoring treatment response in B-lymphoblastic leukemia (B-ALL) is measurable residual disease (MRD) testing. Several testing methodologies, including immunophenotypic (flow cytometric) and molecular (polymerase chain reaction and next-generation sequencing) assays, are currently utilized. Moreover, optimal assays, treatment time points, specimen types, and specimen quality considerations are not established. The goal of this guideline is to establish evidence-based standards and expert recommendations on MRD testing methodologies and specimen considerations for pediatric and adult B-ALL. 

The primary goal of this guideline is to address clinical evaluation of MRD in B-ALL. The evidence-based recommendations will focus on optimal MRD testing methods.

1a. In patients with Philadelphia chromosome negative (Ph-) B-ALL, which method (flow cytometry or NGS) is best for evaluating MRD status at post-induction, post-consolidation, pretransplant, and posttransplant treatment timepoints?

1b. In patients with Philadelphia chromosome positive (Ph+) B-ALL, which method (PCR, flow cytometry, or NGS) is best for evaluating MRD status at post-induction, post-consolidation, pretransplant, and posttransplant treatment timepoints?

2. In patients with B-ALL, do peripheral blood specimens have concordance with bone marrow aspirates for detecting MRD?

3. For bone marrow aspirates from B-ALL patients, what are the optimum and minimum cellularity requirements for accurate assessment of MRD?

• Guideline status: Complete Recommendations and Draft Manuscript
• Collaborators: Association for Molecular Pathology (AMP) and International Clinical Cytometry Society (ICCS)
• Open Comment Period: October 8 – 29, 2025

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