Fig. 1.

(A) Laser speckle patterns captured from a human blood sample showing time-dependent speckle intensity modulation during coagulation at 0, 4, 6 and 10 min following coagulation activation with kaolin. (B) Blood sample cartridge employed for LSR measurements (Grace Bio-Labs). The cartridge consists of a small chamber (volume = 100 μL) made of a blood compatible silicon base sandwiched between thin (0.15 mm) polycarbonate sheets. The clear polycarbonate sheet provides a clear optical window for LSR measurements. (C) Schematic diagram of the LSR optical setup used for blood coagulation assessment. Polarized light (690 nm, 9 mW) from a diode laser (Newport Corp., LPM690-30C) was focused (spot size 100 µm) on the imaging chamber containing ~100 µL of kaolin-activated blood. Cross-polarized laser speckle patterns were acquired at 180° back-scattering geometry via a beam-splitter using a high speed CMOS camera (Basler AG, acA2000-340km) equipped with a focusing lens (Edmund Optics, NT59-872). The captured speckle patterns were transferred to a computer for further processing.