Figure 1

Note that PPA demonstrates a gradual return of platelet aggregation to normal over 3 days. This characteristic of PPA stimulated aggregation makes it useful for measuring gradations of aspirin induced platelet inhibition. AA aggregation remains unresponsive for 3 days and returns to normal function between days 3 and 4. AA stimulated platelet aggregations were used to show if aspirin platelet inhibition was present or absent [31].