Flow cytometry is a powerful analytical technique fundamental for many cell biology and biomedical applications. Flow cytometry makes use of light from lasers to count and profile individual cell types even, when present in a complex heterogenous cell mixture. This is accomplished by funneling cells through a narrow channel and illuminating the cells as they pass through one at a time. Sensors detect the light that is reflected, diffracted, emitted, and refracted from the cells, while computers are employed to process and analyze this data. Analysis of diagnostic molecular markers are the basis for specific cell type identification and sorting. Among numerous other applications, this technique is able to distinguish disease cells from normal cells within a given tissue sample.