Summary
The Ultra-Flo 100 Whole Blood Platelet Counter has proved a useful tool for measuring
platelet aggregation in whole blood, the extent of aggregation being deduced from
the number of single platelets that remain. The technique has allowed us to show that
platelets aggregate spontaneously in citrated blood and in heparinized blood but not
in whole blood collected into EDTA. The aggregation occurs during storage but its
rate is enhanced by stirring and it occurs more readily when the whole blood has been
exposed to plastic rather than glass. It occurs much more readily in whole blood from
some individuals than from others and the process may involve adenosine diphosphate
(ADP). The rate of aggregation in whole blood is enhanced by several aggregating agents
including collagen, ADP and sodium arachidonate which are more usually studied in
platelet-rich plasma.
Keywords
Blood platelets - Platelet aggregation
