Method and apparatus for multiple category threshold and window events counting in flow cytometric studies

ABSTRACT The invention is a method and apparatus for counting multiple categories of combinations of threshold and window event signals generated by a multi-parameter flow cytometer instrument. The generation of event signals for each monitored parameter indicates that the detected parameter signal is above one or more pre-deter-mined thresholds and/or within one or more windows or ranges. Counting the occurrence of each of said combinations is accom-plished by using the event signals as an address code which is applied to a pre-programmed memory. Said pre-programmed memory generates data corresponding to a relative address location for each combination of the multiple-category event combinations. The relative address is used by a microprocessor to access a particular address location of a random access memory, the data at said particular address location being incremented each time the data is so accessed. The data in the address locations of the random access memory may be displayed or used for analysis or experiment control purposes.