Patent ID: RE38688

Claim:
An analytical device for the detection or determination of a component in a fluid wherein said component is an analyte with bioaffinity binding properties, comprising a layer of a plurality of substantially planar zones adjacent one another and in absorbent contact with one another, said layer including: a mobile phase application zone (MPAZ), an intermediate zone (IZ) and an adsorption zone (AZ), liquid being capable of moving by adsorption from said MPAZ through said IZ to said AZ, and wherein said IZ further comprises a solid phase zone (SPZ) having at least one unlabelled reactant, capable of interactions of biological affinity with at least one analyte; at least one unattached, labelled reactant (conjugate), capable of interactions of biological affinity with said at least one analyte, disposed in an area between the MPAZ and the SPZ; and an analyte application zone diaposed at said MPAZ or in between said MPAZ and said AZ, wherein after application of said at least one analyte, said at least one analyte is reacted with said reactants in said layer and is detected in said layer.