Platelet loss on exposure of citrated blood to various foreign surfaces.

Citrated whole blood was rotated in tubes or closed loops of tubing and the percentage of platelets lost on exposure to the surface of the container was noted. Platelet loss in the presence of uncoated glass surfaces (mean loss 31%) was significantly less than in the presence of glass siliconed with two different reagents (82% and 86%). Platelets adhered to siliconed glass but not to uncoated glass. Other inert surfaces also resulted in a high degree of platelet loss: Teflon 90 per cent, silicone rubber 85 per cent, Parawax 84 per cent, polysytrene 82 per cent, polyethylene 79 per cent, polypropylene 60 per cent, and polycarbonate 58 per cent. One lot of polyvinyl chloride transfusion grade tubing resulted in only 2 per cent loss of platelets, but other lots varied between 35 and 84 per cent. Loss of platelets on exposure to the surface of plastic containers may have to be considered when evaluating new materials for preparation of blood components.