A method and system incorporating a process for analyzing a sample to be tested to determine the presence of or to quantify an analyte in the sample. The process employs a reaction which produces a reaction medium derived from the sample that possesses fluorescence properties, in response to illumination by a light source. The process includes illuminating the sample and detecting a fluorescent signal, introducing the reaction medium, and illuminating the sample and detecting a second fluorescent signal from the sample. The process further includes processing the two signals to determine which portion of the fluorescent signal is produced solely by the reaction medium.