Flow cytometers are machines constructed to measure and record flurescence on particles or cells stained with fluorochrome and flowing in suspension past an excitation source, typically a laser beam.

The fluorescence levels of the individual cells are captured by a photomultiplier tube, converted into an electric pulse, and stored and analyzed by a computer.

The cells can also be stained with multiple fluorochromes and can be excited by two different laser beams. This technique known as multiparameter flow cytometry, helps analyze several cellular components and their relationships.

Some other cellular features, such as light scattering at small angles, pulse width, or electrical conductivity, related to some extent to cell seize, can also be measured. [Read more...]