Minimal residual disease (MRD) is the most important prognostic predictor in children with acute lymphoblastic leukemia(ALL). MRD at different time points has different clinical significance.Results of MRD detection in the early stages treatment may reflect the overall effect of chemotherapy in children with ALL, which is an important reference basis for risk classification in the ALL chemotherapy regimen. Currently, real-time quantitative polymerase chain reaction (RQ-PCR) and multi-parameter flow cytometry (MFC), fluorescencein situhybridization (FISH) and new technologies were commonly used in MRD detection. Among them, RQ-PCR has higher sensitivity in MRD detection than FCM, but it is more time-consuming. Appropriate MRD detection methods should be selected according to different purposes in clinical application. As the latest development of MRD detection technology, digital droplet PCR (dd-PCR) and next-generation sequencing (NGS) can further improve the sensitivity of MRD detection, and have more advantages in early identification of ALL children with high risk of relapse. This article summarizes the relationship between MRD and risk stratification of ALL diagnosis and treatment, samples selection of MRD detection, MRD detection methods and its selection.
