Comparison of Euroflow and Conventional Flow Cytometry Protocols for Minimal Residual Disease Detection in Pediatric B-Cell Acute Lymphoblastic Leukemia

Abstract

Acute Lymphoblastic Leukemia (ALL) is the most frequent hematological malignancy in childhood, and its prognosis is strongly linked to the monitoring of Minimal Residual Disease (MRD). Flow cytometry (FC) is the gold standard for MRD detection, but methods vary widely between laboratories, often leading to discrepancies in sensitivity and reliability. This study aimed to quantitatively and qualitatively compare two flow cytometry protocols—the standardized EuroFlow method and a conventional, laboratory-developed protocol—for MRD detection in pediatric B-cell ALL patients. A total of 228 bone marrow samples from 76 pediatric patients at IREN SUR were analyzed. The results, benchmarked against an external reference (INSNSB protocol), showed that 35.5% of patients were MRD-positive, predominantly in the female and older pediatric (11–15 years) subgroups. The EuroFlow protocol demonstrated a consistent 100% accuracy across all age and sex strata, whereas the conventional method showed diminished accuracy, falling to 83.3% in the female 11–15 years group. Crucially, both protocols maintained 100% specificity (precision). Correlation analysis indicated perfect diagnostic concordance for EuroFlow (kappa=1.000) and superior quantitative correlation with the reference for normal B-lymphoblasts (R=0.9798). These findings conclusively establish EuroFlow as the more reliable and robust protocol for MRD detection in a clinical setting, recommending its adoption to standardize diagnostic practice and improve relapse prediction.