Abstract: A diagnostic test device comprising an absorbent medium adapted to receive and retain a measured amount of fluid containing the substance to be tested and reagents adapted to contact said fluid to provide a visual determination of the presence and/or concentration of the substance, wherein the absorbent medium comprises a substantially non-swellable material of substantially uniform and constant porosity and thickness.

Abstract: A diagnostic test device comprising a first and second sheet attached at a leading edge; an absorbent medium intermediate said first and second sheet in spaced relationship to said sheets. The fluid containing the substance to be analyzed is placed on the absorbent medium. Compressive force would then be applied to the test device to remove excess fluid from the absorbent medium and to bring the fluid into contact with the first and second sheets which contain reagents adapted to react with the substance to provide a colorimetric determination of the presence and/or concentration of the substance.