An optical coagulation monitor and the method of monitoring blood coagulation status are disclosed. The method includes positioning a sample probe containing an optical fiber within a circulating blood; transmitting a low-coherence light through the optical fiber into the blood; detecting dynamic light scatter signals generated by the blood within a coherence volume and received through the optical fiber; analyzing the dynamic light scatter signals in comparison to a predetermined coagulation criterion; and reporting the coagulation status of the blood. The method can be used for monitoring blood coagulation status in vivo or in vitro in real time. Further disclosed is a method of determining blood clotting time in vitro using the optical coagulation monitor
