The CultreCoat® Vascular Permeability Assay was created to accelerate the screening process for signal transduction pathway modulators and compounds that influence vascular permeability. This assay offers a flexible, standardized, high-throughput format for quantitating the degree to which genes or compounds can influence the maintenance of endothelial cell-to-cell adhesion. This assay employs a simplified Boyden chamber design with a one micron polyethylene terephthalate (PET) membrane coated with collagen I. Ports within the migration chamber (top) allow access to the assay chamber (bottom) without dismantling the device. This design is easier to use, prevents contamination, and is adaptable for robotic high throughput systems. The assay chamber may be directly analysed in a 96 well plate reader, eliminating transfer steps that introduce additional variability to the assay.