Blood separation device comprising a filter and a capillary flow pathway exiting the filter

Claim 1

In a clinical diagnostic device comprising a housing having a fluid inlet port, a vented reaction area, and a unitary capillary pathway connecting said inlet port and said reaction area, said housing constructed such that said pathway conducts liquid exclusively as a result of capillary pressure originating in said pathway, the improvement which comprises: a low-pressure filter in said inlet port and directly adjacent to said capillary pathway, wherein said filter is constructed so as to separate agglutinated red blood cells from plasma, wherein said filter further contains a soluble agglutinin for agglutinating red blood cells selected from the group consisting of antibodies and lectins, wherein whole blood applied to said inlet port contacts said soluble agglutinin concurrently with contacting said filter and plasma is separated from whole blood which flows into said capillary pathway in the absence of externally applied pressure.