Evaluation of the in vitro and ex vivo blood compatibility of primary reference materials.

The blood compatibility of the primary reference materials, low density polyethylene and polydimethylsiloxane, was evaluated using human in vitro and human ex vivo test devices, and was compared with that of polyetherurethane and polyvinylchloride. The effect of the materials on in vitro platelet activation was studied by measurement of platelet factor 4 release by enzyme immunoassay. The adsorption of fibrinogen and platelets from human native blood onto the surface of the material was measured using enzyme immunoassay technique. The four materials tested exhibited significantly different effects on in vitro platelet activation. In addition, the materials adsorbed fibrinogen and platelets to a different extent under ex vivo test conditions. Materials, which induced strong in vitro platelet activation, e.g. low density polyethylene and polyvinylchloride, demonstrated high concentrations of fibrinogen and platelets on the surface when tested under ex vivo conditions. Polydimethylsiloxane and polyetherurethane, which induced slight in vitro platelet factor 4 release, absorbed significantly lower concentrations of fibrinogen and platelets from human native blood.