Platelet aggregation testing

The authors review the methods currently used for platelet aggregation testing, which are mainly grouped in two classes: 1. methods measuring the sensitivity of platelets to aggregating agents and to mechanical stimulation in vitro and 2. methods measuring the spontaneous tendency of platelets to aggregate in vivo. Their advantages, their pitfalls and their potential usefulness are reported. The platelet behavior as assessed by the available methods is not strictly related to the true platelet behavior in circulating blood. Therefore much criticism is requested in the interpretation of the results obtained for a given group of subjects with a given method and any unallowed extrapolation must be avoided.