Immunophenotyping is a laboratory technique used to analyze the types and characteristics of cells in a sample based on the specific markers (antigens) present on their surface. While the diagnosis of CML is primarily based on the presence of the BCR::ABL1 fusion gene detected by cytogenetic or PCR techniques, immunophenotyping can provide complementary information about the cellular makeup, particularly in the blast crisis. The blasts may be of myeloid, lymphoid, or mixed origin. Knowing the origin (lineage) of the blasts is important for therapeutic purposes.
