Clinical applications of flow cytometry.

OBJECTIVE: To describe the basics of three clinical applications of the flow cytometer. DATA SOURCES: Recent articles and books on flow cytometry and laboratory diagnosis. STUDY SELECTION: Not applicable. DATA EXTRACTION: Performed by the author. DATA SYNTHESIS: Immunophenotyping is the classification of cells based on antigens present on their surfaces. These antigens can be detected and quantified by a flow cytometer using monoclonal antibodies conjugated to fluorescent dyes. Reticulocytes are immature red blood cells that contain varying amounts of RNA and DNA. They can be stained with a fluorescent dye and enumerated by a flow cytometer. DNA ploidy analysis of solid tumors involves staining the nuclei of cells with a fluorescent dye. The amount of DNA in each cell is determined, and the percentage of cells in the S phase is calculated. CONCLUSION: Flow cytometry is a relatively new technology in the clinical laboratory. There are many clinically useful applications for which it is suited. As the technology continues to grow, so will the use of the flow cytometer.