Apparatus for determining platelet inhibitor response

An apparatus is provided for performing an activated clotting time test on a sample of blood containing platelets, the apparatus comprising a plurality of test cells, said cells being adapted for receiving an aliquot portion of said sample, wherein each of said cells comprises an anticoagulant and a platelet inactivating agent, and wherein at least one of said cells further comprises a clotting activator, wherein a clotting time is determined for each of said aliquot portions, and wherein a relative clotting time for each of said aliquot portions comprising the clotting activator is determined as compared to a reference clotting time for said at least one cell containing no clotting activator, wherein said relative clotting times in said cells are determinative of the clotting activation of said clotting activator.