A planar microfabricated fluid

Many blood tests must be performed on plasma without cellular matter present. Ln the standard laboratory protocol, pure plasma is obtained through centrifugation. in order to produce a miniaturized blood sensor, a method to separate plasma other than centrifugation is needed. We describe the design, fabrication, and testing of a fluid filter that fulfils this need, and also has some features of general interest. Results from a particular device show that we can easily remove 16 mu m diameter spheres from the fluid. This filter can be reusable, can potentially remove particles as small as 0.1 mu m, and is easily fabricated.