This work reports on development and characterization of an on-chip microfluidic handling system for application in preclinical anti-platelet drug screening. A reciprocating elastomeric micropump/mixer design is presented for use with whole human blood, utilizing flexible structural and actuation properties to manage hemodynamics for an on-chip platelet thrombosis assay on fibrillar collagen. The hemocompatibility of the design is assessed across a range of operational configurations, demonstrating equivalent or superior performance to common microcapillary systems at a range of physiologically relevant shear conditions. Surprisingly efficient mixing phenomena are briefly investigated, validated using dyes within the molecular weight range of common antiplatelet therapies. Finally, a proof-of-concept preclinical application is explored, demonstrating that this prototype can act as a real-time assay of anti-platelet drug pharmacokinetics, compared to an equivalent microcapillary system.