Flow cytometry: an overview.

Flow cytometry is an innovative technology that measures certain cell parameters as the cells flow in a fluid stream and in single file past an analytical laser light source. Clinical applications of flow cytometry currently utilized in the laboratory include cell surface antigen determinations or immunophenotyping of hematologic cells, DNA analysis of hematopoietic malignancies and solid tumors, and measurement of CD4 (T helper/inducer cell) absolute counts and T helper/T suppressor (CD4/CD8) ratios in the evaluation of immune deficiency. Flow cytometry often offers a more rapid, sensitive, accurate, and quantitative means of analyzing a particular cell population in a heterogeneous cell suspension as compared to more traditional microscopic methods. This article is intended to provide a general understanding of the technological basis of how a flow cytometer functions as well as an overview of both current and future flow cytometric clinical laboratory applications.