A machine for automatic in vitro detection of analytes, the machine being of the type comprising an optical reader device (30) capable of detecting the optical response of the reaction solution to electromagnetic stimulation using a photoelectric receiver (70) that is carried by a movable carriage (32) of the machine and that moves under automatic control in order to bring the photoelectric receiver into various positions, each corresponding to various respective analysis zones (26′), the machine being characterized in that the photoelectric receiver (70) forms part of a spectrometer (64) capable of delivering a chromatic spectral decomposition of the optical response. The invention also provides methods of automatic in vitro detection and/or quantification of analytes. In one method, a chromatic spectral decomposition of the optical response is acquired and two distinct optical agents are detected separately by means of said spectral decomposition.
