This presentation will focus on the use of microchip-based hydrodynamic focusing to develop a mimic that allows both mechanical deformation of erythrocytes and quantification of the adenosine triphosphate (ATP) that is subsequently released in response to this deformation. The microfluidic regime allows an accurate investigation of vasodialtion processes while mimicking the vasculature dimensions found in vivo. In this mimic, two sheath streams of luciferin/luciferase solution are used to focus and deform an erythrocyte flow stream. The focusing width is changed by simply manipulating the sheath flow rate. This allows a variety of focusing cross-sectional areas to be studied using single point chemiluminescent detection. In vitro mimics of the microvasculature can be utilized with human samples to examine the role of vasodialtion in conditions such as pulmonary hypertension and type II diabetes. We will present data from both New Zealand white rabbits and human samples that demonstrate a significant increase in the release of ATP as a function of increased deformation stress. For example, one sample of rabbit erythrocytes released 0.80 (± 0.13) µM ATP when focused to a cross-section of 3480 µm², while focusing the same sample to a smaller cross-section (1160 µm²) led to a release of 6.43 (± 0.40) µM ATP. We have also found that variation of the width and angle of the sheathing flows can reproducibly focuses the centralized stream to widths ranging from 7 µm to 70 µm, which spans the dimensions of the microvasculature (arterioles to capillaries) found in vivo.