A method of analysing a sample to be tested to determine the presence of, or to quantify, an analyte capable of being present in said sample, employing a reaction which produces a reaction medium derived from said sample and which possesses fluorescence properties, said reaction medium being located within a well, said reaction medium and said well forming an analysis assembly which possesses fluorescent properties in response to an illumination from a light source which produces a light signal, said light source being moveable along a surface S1 (26, 206, 207) comprising a first edge, a wall and a second edge of the well, said method comprising the following steps: - illumination of the surface S1 (26, 206, 207) of the well by means of the light source, before introduction of the reaction medium into the well from n different positions including the positions relative to the first edge, to the wall and to the second edge for the light source; - detection of a fluorescence signal emitted by the well, for each different position n including the positions relative to the first edge, to the wall and to the second edge for the light source, in response to the illumination and before introduction of the reaction medium into the well to produce a first signal; - illumination of the analysis assembly by means of the light source, after introduction of the reaction medium into the well, from n different positions including the positions relative to the first edge, to the wall and to the second edge for the light source; - detection of a fluorescence signal emitted by the analysis assembly, for each different position n including the positions relative to the first edge, to the wall and to the second edge for the light source, in response to the illumination and after introduction of the reaction medium into the well to produce a second signal; - performing a calculation operation comprising the first signal representing the variations in intensity of the fluorescence signals detected for each different position n including the positions relative to the first edge, to the wall and to the second edge for the light source, in response to the illumination and before introduction of the reaction medium into the well and the second signal for each different position n including the positions relative to the first edge, to the wall and to the second edge for the light source, in response to the illumination and after introduction of the reaction medium into the well to produce a resulting signal for each different position n including the positions relative to the first edge, to the wall and to the second edge and corresponding to the emission of the fluorescence signal produced solely by the reaction medium. - illumination of the surface S1 (26, 206, 207) of the well by means of the light source, before introduction of the reaction medium into the well from n different positions including the positions relative to the first edge, to the wall and to the second edge for the light source; - detection of a fluorescence signal emitted by the well, for each different position n including the positions relative to the first edge, to the wall and to the second edge for the light source, in response to the illumination and before introduction of the reaction medium into the well to produce a first signal; - illumination of the analysis assembly by means of the light source, after introduction of the reaction medium into the well, from n different positions including the positions relative to the first edge, to the wall and to the second edge for the light source; - detection of a fluorescence signal emitted by the analysis assembly, for each different position n including the positions relative to the first edge, to the wall and to the second edge for the light source, in response to the illumination and after introduction of the reaction medium into the well to produce a second signal; - performing a calculation operation comprising the first signal representing the variations in intensity of the fluorescence signals detected for each different position n including the positions relative to the first edge, to the wall and to the second edge for the light source, in response to the illumination and before introduction of the reaction medium into the well and the second signal for each different position n including the positions relative to the first edge, to the wall and to the second edge for the light source, in response to the illumination and after introduction of the reaction medium into the well to produce a resulting signal for each different position n including the positions relative to the first edge, to the wall and to the second edge and corresponding to the emission of the fluorescence signal produced solely by the reaction medium.