Guidelines & Consensus
Guidelines for Measurable Residual Disease Assessment in Acute Lymphoblastic Leukemia
Kotrova et alBlood
Measurable residual disease (MRD) assessment is critical for risk stratification, response evaluation, and relapse detection in acute lymphoblastic leukemia (ALL). However, substantial international variability in sampling strategies, detection techniques, reporting thresholds, and interpretation criteria has limited cross-trial comparisons and clinical standardization. To address these variations, an international expert panel representing leading pediatric and adult study groups and reference laboratories developed consensus recommendations through a structured survey of current practices followed by a multi-round Delphi process.
Consensus was achieved on 38 of 41 statements across three primary domains: pre-analytical requirements, technical and nomenclature standards, and MRD-based remission and relapse definitions. The panel endorsed bone marrow as the reference specimen for MRD testing and advised prioritizing MRD results over cytomorphology when discordant findings arise. In addition, the guideline adopted a standardized MRD assay nomenclature and defined frameworks for risk- and actionability-guided late MRD monitoring, confirmation of MRD reappearance, and MRD-informed relapse assessment.
Areas without consensus included the choice of anticoagulant for PCR-based MRD assays, the interpretation of isolated BCR::ABL1 reconversion, and whether MRD should be used exclusively to define remission. The resulting cross-age recommendations provide a practical framework to standardize ALL MRD testing and support clinical decision-making.
Key Takeaways
- An international Delphi process reached consensus on 38 of 41 statements across pre-analytical requirements, technical and nomenclature standards, and measurable residual disease (MRD)-based remission and relapse definitions for pediatric and adult acute lymphoblastic leukemia.
- The panel endorsed bone marrow as the reference specimen for MRD evaluation and recommended prioritizing MRD findings over cytomorphology whenever results are discordant.
- Consensus was not achieved regarding anticoagulant selection for PCR-based MRD, the clinical interpretation of isolated BCR::ABL1 reconversion, or the exclusive use of MRD to define remission.