Assessing blood coagulation status with laser speckle rheology.

We have developed and investigated a novel optical approach, Laser Speckle Rheology (LSR), to evaluate a patient's coagulation status by measuring the viscoelastic properties of blood during coagulation. In LSR, a blood sample is illuminated with laser light and temporal speckle intensity fluctuations are measured using a high-speed CMOS camera. During blood coagulation, changes in the viscoelastic properties of the clot restrict Brownian displacements of light scattering centers within the sample, altering the rate of speckle intensity fluctuations. As a result, blood coagulation status can be measured by relating the time scale of speckle intensity fluctuations with clinically relevant coagulation metrics including clotting time and fibrinogen content. Our results report a close correlation between coagulation metrics measured using LSR and conventional coagulation results of activated partial thromboplastin time, prothrombin time and functional fibrinogen levels, creating the unique opportunity to evaluate a patient's coagulation status in real-time at the point of care.