Patent ID: 7790362

Claim:
A method for measuring inhibition of platelet aggregation by a P2Y12 antagonist, comprising the steps of: a) providing a platelet containing blood sample from an individual treated with a P2Y12 antagonist; b) contacting said platelet containing blood sample with particles comprising an attached GPIIb/IIIa receptor ligand, adenosine diphosphate (ADP) and prostaglandin E1 (PGE1) under conditions suitable for agglutination of said particles mediated by said platelet in said blood sample, wherein said ADP has a final concentration of 2 to 35 μM and said PGE1 has a final concentration of 2 to 30 nM; and c) assessing said agglutination to determine the level of inhibition of platelet aggregation by said P2Y12 antagonist in said individual, wherein a reduced level of agglutination indicates whether said individual has reduced ability to form platelet aggregation in response to said P2Y12 antagonist treatment.