Four channel platelet aggregometer

Platelet aggregation was measured using a four-channel platelet aggregometer (Chrono-Log Corp., USA) after the addition of 0.1 μg/mL collagen or 2 μM ADP. PRP was incubated for 5 min at 37 °C. After incubation, platelet aggregation was determined as the level of light transmission monitored for 5 min. Platelet aggregation was expressed as percentage of the platelet-poor plasma (PPP) transmission values. Bleeding time was measured by the tail transection model. After treatment, the tail tip was transected with a scalpel at a point that measured 1 mm in diameter. Bleeding was assessed every 30 s using a filter paper, and the time to clot formation defined the bleeding time. Clotting time was determined by collecting blood into three separated test tubes prewarmed at 37 °C to obtain an average result. Blood clotting was tested by tipping the tube back and forth every 30 s, and clotting time was determined when blood does not flow out from tubes when tilted horizontally. Platelet count was determined using a blood cell counter HEMAVET950 (Drew Scientific, USA). d-dimer level determination was performed in plasma by use of Rat d-Dimer ELISA Kit according to instructions by the manufacturer (Abbexa, UK).