Patent ID: 8021625

Claim:
A flow immunoassay device for testing a fluid specimen for the presence of an analyte, wherein said device comprises: a first chamber shaped and dimensioned to accept said specimen and be subjectable to a source of a mobilizable labeled binding member bindable to said analyte; a second chamber holding at least one test result signal generator responsive to an amount of said analyte bound to said labeled binding member; and, a flow interrupting formation located on a fluid path between said first and second chambers; wherein said flow interrupting formation comprises: a first porous diffusive structure comprising; a lower upstream entry portion; an upper trap portion; and, a lower downstream exit portion; wherein said fluid flows to said flow interrupting formation primarily under the force of gravity alone; wherein an initial fluid front of said fluid said entry portion is automatically diverted upwardly primarily under the force of capillarity alone and against the force of gravity into said trap portion; wherein said fluid flows through said generator primarily under the combined forces of gravity, siphoning and capillarity; and, whereby a first affinity binding reaction between said analyte and said labeled binding member is substantially completed before said fluid enters said second chamber.