An enhanced diffraction based biosensor system and method are provided for detecting an analyte of interest in a test medium. The system incorporates at least one additional detection tag substance with the analyte of interest, the tag emitting a measurable parameter that is different from optical diffraction characteristics of the analyte. The biosensor may be a "fluoroptical" system wherein the detection tag is a fluorescence emitting substance, including fluorescent-labeled diffraction enhancing elements. The enhanced diffraction biosensor system may determine the presence of analytes in biological fluids both qualitatively and quantitatively.