Cell counting

A method for determining the absolute counts of cells of interest per unit volume of a sample, said method comprising:

• (a) providing a container containing:
• (i) a matrix adhered to at least one wall of said container, said matrix being semi-solid, of gel-like consistency, or in dry form;
• (ii) a predetermined quantity of reference microparticles, distinguishable from a labeled cell-binding agent, disposed in or on said matrix such that substantially all the reference microparticles are thereby attached to said container;
• and
• (iii) the labeled cell-binding agent in or on the matrix, wherein the labeled cell-binding agent is capable of binding to and identifying said cells of interest in the sample;
• (b) adding a known sample volume of said sample to said container, whereby:
• (i) said known sample volume, labeled cell binding agent, and matrix are mixed;
• (ii) said labeled cell-binding agent binds to cells of interest are in said known sample volume;
• and
• (iii) said reference microparticles are released into the added known sample volume;
• (c) counting, in a portion of the sample volume obtained in (b), both the number of said cells of interest identified as cells bound to said labeled cell-binding agent and the number of reference microparticles, and from this determining the ratio of said cells of interest per reference microparticles in said portion of the sample volume;
• and
• (d) determining an absolute count of said cells of interest in said known sample volume by multiplying the ratio of cells of interest per reference microparticle obtained in (c) by the predetermined quantity of reference microparticles in said known sample volume.