A method of analyzing a sample to be tested to determine the presence of or to quantify an analyte in the sample, employing a reaction which produces a reaction medium derived from the sample and which possesses fluorescence properties, the reaction medium being located within a well, the reaction medium and the well forming an analysis assembly which possesses fluorescent properties in response to illumination by a light source producing a light signal, the light source being movable along a surface S1 of the well.