Method and device for determining the coagulation time of a blood sample, and reaction vessel

A device for determining the coagulation time of a blood sample to be analyzed, the determining device comprising:

• a receiving housing in which a reaction cuvette containing the blood sample to be analyzed and a ferromagnetic ball is intended to be received, the reaction cuvette delimiting a concave raceway whose concavity is directed upwards and on which the ferromagnetic ball is placed,
• a magnetic field generation system configured to generate a magnetic field capable of displacing the ferromagnetic ball along the raceway in an oscillatory movement when the reaction cuvette is received in the receiving housing,
• an emission member configured to emit an incident light beam in the direction of the blood sample to be analyzed when the reaction cuvette is received in the receiving housing, the incident light beam being configured to be at least partially obscured by the ferromagnetic ball during at least one part of the movement of the ferromagnetic ball along the raceway,
• a detection member configured to detect at least one light beam transmitted through the reaction cuvette and coming from the incident light beam and to output a measurement signal (SM), and
• a processing unit configured:
• to carry out a first processing of the measurement signal (SM) so as to provide a first signal (S1) representative of the variation of at least one physical quantity representative of the movement of the ferromagnetic ball,
• to carry out a second processing of the measurement signal (SM) so as to provide a second signal representative of the variation of at least one optical property of the blood sample to be analyzed,
• to determine a first value (t1) of the coagulation time of the blood sample to be analyzed from the first signal, and
• to determine a second value (t2) of the coagulation time of the blood sample to be analyzed from the second signal.