Prior to implantation, the hemocompatibility of implants needs to be analyzed and must fulfil the guidelines developed by the International Organization for Standardization (ISO 10993-4). Several in vitro testing models are available to assess the hemocompatibility of implants by incubating them in human blood under static, agitated, or shear flow conditions. The first step is evaluation of the thrombogenicity of blood-contacting devices under static conditions. Subsequently, assessment of the hemodynamic behaviour under dynamic flow is crucial, namely the shear-induced activation of blood cells and proteins, as well as the flow dependent transport of procoagulant cells and proteins. Recognizing the importance of the interaction of blood flow and the biomaterial surface in a dynamic context, studies have focused on developing in vitro testing platforms such as tubular and cone-and-plate viscometers, parallel plate flow chambers, and microfluidic flow chambers. Among these techniques, the use of microfluidic devices provides the most efficient approach because of the short analysis times, versatility of fabrication protocols, minimal consumption of reagents, high resolution and sensitivity of fluid manipulation, and portability (Figure ). The advantages of microfluidic devices have driven the development of organ-on-a-chip (OOC) technology to model conditions present in the human bloodstream, specifically vascular-like flow conditions and vascular-like microenvironments. Recently, a microfluidic platform for in vitro testing was fabricated to compare the thrombogenicity of LIS and anti-CD34 coated ePTFE vascular grafts under arterial wall shear stress and with and without ECs under flow conditions. Using this "vascular graft-ona-chip" device, the thromboresistance of the coated vascular grafts was established under flow conditions and the attenuated thrombin generation and fibrin deposition was monitored in real time, thus facilitating the translation of synthetic grafts into the clinical space (Figure ). Once results from benchtop testing have met the guidelines developed by ISO 10993-4 and the biomaterial is safe for use in vivo, computational in silico testing and studies in animals are the next steps. Common animal species used for such testing include mice, rabbits, goats, and pigs.