Calibration of flow cytometry detector systems

A method of determining the relative intensity of the fluorescence signal measured by a fluorescence activated signal measured by a fluorescence activated cell sorter is described. The calibration process is a multistep procedure, in which the signal gain due to the amplifier module is first evaluated, followed by determination of the photomultiplier response as a function of tube voltage for each fluorochrome and filter combination of interest. Using these values, a simple mathematical calculation then determines the relative intensity of a fluorescent signal, even for samples differing in intensity by several orders of magnitude.