"Flow cytometry is the most practiced member of a family of technologies known variously as automated, analytical, or quantitative cytology. As the term implies, flow cytometry is the measurement (-metry) of cellular (cyto-) properties as they are moving in a fluid stream (flow), past a stationary set of detectors. The melding of such diverse areas of scientific endeavors and technical accomplishments as computer science, laser development, electronics, hydrodynamic focusing and ink-jet technology, optics and light detection, monoclonal antibodies, and DNA analysis has produced an instrument, the flow cytometer, which is capable of rapid, quantitative, multiparameter analysis of heterogeneous cell populations on a cell-by-cell basis (single cell analysis)."
"In little more than a decade, flow cytometry has evolved from a highly specialized research tool to a commonplace clinical assay. Clearly the impetus for this change has been that flow cytometry is the only technique capable of quantitative measurements of multiple features of individual cells in a rapid manner."
"In the simplest terms, a flow cytometer operates by causing a fluid stream to pass single file through a beam of light, usually generated by a laser. The photons of light, which are scattered and emitted by the cells following their interaction with the laser beam, are separated into constituent wavelengths by a series of filters and mirrors. This separated light falls upon individual detectors that generate electrical impulses, or analog signals, proportional to the amount of incident light striking the detectors. Each analog signal is converted to a digital signal, a number which is accumulated in a frequency distribution, or histogram (see figure below). Therefore, the resultant number is proportional to the amount of light emitted from, or scattered by, the individual cell."
quotations from: J. Philip McCoy, Jr., Ph.D.,"Basic Principles in Clinical Flow Cytometry" in Flow Cytometry and Clinical Diagnosis, (eds: Keren, Hanson, Hurtubise), ASCP Press, Chicago, 1994, pp. 26-55.
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Revised: May 22, 1996
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