Patent ID: 8574828

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 the platelet containing blood sample with particles comprising an attached GPIIb/IIIa receptor ligand, adenosine diphosphate (ADP) and prostaglandin El (PGE1) under conditions suitable for agglutination of said particles mediated by the platelet in the blood sample, and (c) assessing the agglutination to determine the level of inhibition of platelet aggregation by the P2Y12 antagonist in the individual, wherein the level of agglutination indicates whether the individual has reduced ability to form platelet aggregation in response to the P2Y12 antagonist treatment.