Embodiments of a platelet testing system include an analyzer console device and a blood testing cartridge configured to releasably install into the console device. The cartridge device is configured with one or more measuring chambers and one or more mixing chambers that are fluidically connected within the cartridge device that enable the mixing of saline and a blood sample to a desired dilution. Additionally, the cartridge device is further configured with a cartridge slider that provides a reagent bead to the saline and blood mixture at a desired time. As such, one or more platelet activation assays can be conducted by measuring, through cartridge electrodes of the cartridge device, the detectable changes in platelet activity within the blood and saline mixture.