Basics of flow cytometry.

The basics of flow cytometry are described. Cytometry is the measurement of cells; the flow cytometer performs this measurement quickly and reproducibly. Single cells in suspension are presented to a light source through hydrodynamic focusing. The resultant scattered light and fluorescence are collected and converted to electrical pulses, which are digitized for computer analysis. Frequency distributions can be viewed as single- or multiple-variable histograms for evaluating cell measurements. The versatility of flow cytometry is demonstrated by the types of samples it can analyze, characteristics it can measure, and applications in multiple laboratory sciences. Flow cytometry has been adapted easily and rapidly from a research tool to a clinically important procedure.