An optical analysis disc includes grooves defining corresponding laser-readable tracks and trigger marks that identify respective target regions on the disc. The trigger marks are implemented as a radial interruption of the grooves to thereby produce an increased reflection of a laser beam. There is also provided an optical analysis disc system including a trigger mechanism having a trigger detector adapted to detect interruptions in grooves of an optical analysis disc. A related method for triggering through interrupted grooves of an optical analysis disc includes detecting interruption in the grooves, generating an electrical reflection signal corresponding to the interruptions detected, and elaborating said reflection signal, so that to generate a trigger signal.