Common flow cytometry pitfalls in diagnostic hematopathology

Flow cytometry (FC) has proven to be an extremely versatile and useful tool in the diagnosis and monitoring of hematological diseases in addition to numerous other applications. Major advances in electronics, software, and reagents over the past years have simplified some aspects of FC, while at the same time the ability to combine 8-10 antibodies in a single tube can create both technical and interpretation issues that are more difficult to detect when using only 3-4 color combinations. Use of multiparameter panels can facilitate identification of abnormal populations; however, characteristics of the neoplastic population may create potential diagnostic pitfalls. An understanding of normal immunophenotypic patterns in states of rest, recovery, and activation is a critical first step in order to appropriately identify the abnormal populations that characterize hematopoietic neoplasms. Additionally, incorporation of newer therapeutic strategies, in particular targeted therapies, can confound standard methods for flow cytometric data analysis and knowledge of the impact of therapy on flow cytometric data is critical for accurate data interpretation. This manuscript will review preanalytical, instrument, and interpretation issues that may lead to incorrect interpretation of results.