Multiparameter immunophenotypic analysis of fine needle aspiration biopsies and other hematologic specimens by laser scanning cytometry

OBJECTIVE: To test the new laboratory technology of laser scanning cytometry with respect to immunophenotyping of all types of hematologic and lymphoreticular specimens and particularly those of limited size, such as fine needle aspiration biopsies and hypocellular body fluids. STUDY DESIGN: Over the course of two years, 343 hematologic and lympho reticular specimens of all types were immunophenotyped by laser scanning cytometry using methodologies modified from those of conventional flowcytometric immunophenotyping. Results for all cases were corroborated with histology and/or cytology and, for some cases, immunohistochemistry and/or flow cytometric immunophenotyping. RESULTS: Over 98% of the 343 cases were successfully immunophenotyped by laser scanning cytometry. These included many hypocellular specimens, such as 38 fine needle aspiration biopsies and 33 body fluid specimens. CONCLUSION: Laser scanning cytometry is a new laboratory technology with several significant advantages relative to flow cytometry for immunophenotypic analysis of hematologic malignancy. The laboratory techniques are simplified, and antibody usage is reduced by 80%. Even more important, full-panel immunophenotyping with multiple antibodies can be performed on specimens as small as 50,000 cells total, making the tech nology particularly relevant to cytopathology. After immunophenotypic analysis, specimens can be stained for light microscopic examination, and individual cells meeting user-defined antigenic or physical characteristics can be automatically relocalized.