We have standardized a new chemotaxis chamber that uses fluorescence as the cellular marker for the measurement of leukocyte migration in vitro in disposable 96-well microplates. This new fluorescence-based assay is a robust assay because filter pore size, cell density, filter composition, and filter thickness do not affect PMN migration towards interleukin-8 or the complement fragment, C5a. When compared to two separate chemotaxis assays in which the migrated cells are counted
visually, the fluorescence-based assay was more rapid, less labor intensive, and more sensitive. This new assay is a significant advance in the measurement of leukocyte migration in vitro.