The present invention provides a low cost imaged-based system for detecting, measuring and/or counting labeled features of biological samples, particularly blood specimens. In one aspect, the invention includes a system for imaging multiple features of a specimen that includes one or more light sources capable of successively generating illumination beams each having a distinct wavelength band and a plurality of differentially excitable labels capable of labeling a specimen comprising multiple features, such that each different feature is labeled with a different differentially excitable label. System of the invention may further include a controller operationally associated with the one or more light sources for successively directing illumination beams onto the specimen so that each of the different differentially excitable labels is successively caused to emit an optical signal within the same wavelength band, an optical system capable of collecting such emitted optical signals and forming successive images corresponding to the labeled features of the specimen on a light-responsive surface to form successive sets of image data thereof, and a disposable cuvette for collection and optical analysis of non-red blood cells.