This invention is a disposable cartridge for use at the patient side to perform traditional coagulation assays on fresh whole blood or blood derivative samples. The steel support structure may be a hollow, U-shaped steel tube having first and second attachment features at distal ends thereof for attachment to a lower seat structure. 4 \u03a9\xb7cm or less when compressed to a density of 1. The blade assemblies may be positioned on the shafts so that they intermesh through each other while simultaneously moving through the common volume.