EVALUATING FLUORESCENCE SENSITIVITY ON FLOW CYTOMETERS - AN OVERVIEW

The current paradigms for assessing fluorescence sensitivity on flow c ytometers do not provide an adequate assessment of an instrument's abi lity to detect and measure weak fluorescence on stained particles. The capability to resolve dimly stained populations depends on two factor s: the background noise (B), and the efficiency (Q) with which the flu orescence from the fluorochrome molecules are concerted to photoelectr ons. Any single statistical measure of fluorescence histogram distribu tions will be unable to uniquely characterize an instrument. Therefore , neither of the routinely used methods (detection threshold and delta channel) measure sensitivity completely and unambiguously We show the Limitations of these methods and propose that instrument sensitivity be characterized in terms of both background noise and detection effic iency in order to determine better the capability to detect and resolv e weakly fluorescent particles. (C) 1998 Wiley-Liss, Inc.