Patent ID: 7855068

Claim:
A method for observing a target cell in a sample of untreated or substantially untreated whole blood, comprising: a) providing a sample of untreated or substantially untreated whole blood that is suspected of containing a target cell; b) providing a solid substrate, said solid substrate comprising: a multi-layered composition comprising: (i) a first component on the surface of said solid substrate, said first component comprises polyanion layers and polycation layers in an alternating arrangement substantially parallel to the surface of said solid substrate; (ii) a second component contacting said first component, said second component comprises a high affinity binding pair comprising a first member and a second member, wherein the first member binds to said first component, the second member binds to said first member; and (iii) a third component comprising a specific binding agent that binds to said second member of said second component; c) contacting said sample with said solid substrate; d) incubating said sample on said solid substrate for a period of time sufficient to permit said binding agent to specifically bind said target cells present in said sample to said solid substrate; e) washing said solid substrate; and f) manually observing and counting the number of said target cells bound to said solid substrate by light microscopy.