Flow Cytometry in Acute Myeloid Leukemia (AML): A Critical Tool for Accurate Diagnosis, Classification, and Monitoring

BACKGROUND: Flow cytometry is a crucial diagnostic tool in hematopathology. It supports the identification and follow-up of hematolymphoid neoplasms by providing detailed immunophenotypic data and quantification, and is applicable to various specimen types. CONTENT: Classification and management of acute myeloid leukemia (AML), the most common type of acute leukemia in adults, are complex and evolving, guided by International Consensus Classification and World Health Organization 5th edition diagnostic frameworks, as well as the clinically oriented European LeukemiaNet recommendations. These systems stratify AML based on genomic, morphologic, and immunophenotypic features, informing treatment and outcomes. While cytogenetic and molecular data are central to subclassification, flow cytometry remains essential for rapid diagnostic and prognostic insights. This review explores the role of flow cytometry in diagnosing AML, monitoring disease progression, and assessing measurable residual disease, a key relapse and/or outcome predictor. It details how flow cytometry establishes cell lineage, identifies immunophenotypic markers, and predicts genetic alterations in certain subtypes of AML. Examples of analysis strategies and common flow cytometry patterns, as well as references to in-depth recent review articles on the biology, diagnosis and management of AML in the broader context of myeloid malignancies are provided. SUMMARY: Flow cytometry is indispensable in the diagnosis, classification, and monitoring of AML. Its ability to provide precise, quantitative information enables early and accurate diagnosis, optimizes treatment, and enhances posttherapy monitoring. Although sophisticated flow cytometry-based approaches may be limited to specialized laboratories, laboratory medicine professionals benefit from a thorough understanding of this technology.