Patent ID: 8765391

Claim:
A method for assaying a human blood-cell sample to determine the concentration of analyte cells having a given cell-surface antigen comprising: (a) adding to the human blood-cell sample containing analyte cells, heavy dense particles having surface-bound binding agent capable of specific high-affinity attachment to said given cell-surface antigen on the analyte cells, and being effective to specifically react with and bind to cells having the given cell-surface antigen, including analyte cells, to increase the density of the cells, and magnetic particles having immobilized thereto surface-bound binding agent capable of specifically reacting with a second cell-surface antigen that is present on a second cell type in the sample that also contains said given cell-surface antigen, to increase the magnetic susceptibility of cells to which the magnetic particles have bound, (b) with the sample and added heavy dense particles and magnetic particles contained in a two-chamber device having a microchannel column forming a collection chamber and containing a selected medium, and a catch chamber, removing magnetic particle bound cells containing the second cell-surface antigen, and magnetic particles from the sample by application of a magnetic field to the sample adjacent the catch chamber, to draw magnetic particle bound cells into the catch chamber, (c) causing the dense particle-bound cells and dense particles in the cell sample to migrate through the microchannel column, by subjecting the sample to a gravitational or centrifugal force for a period of time sufficient to cause substantially all of the dense particle-bound cells and dense particles, but not non-particle bound cells, to migrate through the selected medium toward the bottom of the column that indicates column volumes corresponding to concentrations of the analyte cells in the sample, and (d) inspecting the microchannel column to detect the concentration of the analyte cells in the sample, based on the volume of cells that migrated through the selected medium toward the bottom of the column.