Sedimentation and adhesion of platelets onto a horizontal glass surface

An experimental method for measuring platelet adhesion to a glass surface and platelet sedimentation rate is described. Anticoagulated platelet-rich plasma is placed on a horizontal glass slide for various contact periods. The number of platelets adhering to the slide per unit area is recorded as a function of time. The experimental results are used to verify theoretical predictions which account for the effect of the slow sedimentation rate of the platelets and for their escape over the potential barrier between them and the solid surface. By a least-squares fit of the theoretical equation to the experimental data, both the platelet adhesiveness, in terms of P the probability to overcome the potential barrier, and the platelet sedimentation rate V are evaluated. A range of values of P and V for healthy humans is presented.