Insight, innovation, integrationHyperactive platelets are observed in conditions where circulatory ATP levels derived from erythrocytes (ERYs) are either low (e.g., diabetes, cystic fibrosis, pulmonary hypertension) or high, as in sickle cell disease due to hemolysis. ATP-mediated platelet homeostasis has not been thoroughly studied due to the desensitizing nature of platelet ATP receptors and a lack of tools enabling a molecular-level examination of their physiological behavior. Here, using such conventional techniques as microscopy, atomic absorption spectroscopy, and aggregometry, evidence is provided suggesting that ATP can exist as an activator or inhibitor of platelet function. Validation of the platelet function was performed by integrating these standard tools with a multi-cellular microfluidic platform to showcase the physiological effect and corresponding mechanisms involving ATP.