Patent ID: 8110393

Claim:
A method for separating and harvesting cells of interest from a whole blood sample, said method comprising the steps of: (a) depositing a predetermined volume of a diluted whole blood sample into a tube, wherein said diluted whole blood sample comprises said cells of interest, said cells of interest having a cell density; and wherein said tube comprises a bottom and a diameter; (b) dispensing a predetermined volume of a density gradient solution at a predetermined rate at said bottom of said tube, thereby providing a layer of said density gradient solution that underlies said diluted whole blood sample, said density gradient solution having a density substantially equal to or slightly higher than said cell density of said cells of interest; (c) centrifuging contents of said tube to produce a cell layer comprising said cells of interest, said cell layer overlying said density gradient solution; (d) advancing a distal end of an aspirating/dispensing probe to a predetermined location within said tube at which probe port, located at said distal end of said aspiration/dispense probe, underlies said cell layer by no more than a predetermined distance, wherein said predetermined distance is based upon a measurement from said bottom of said tube and said cell layer, said predetermined volume of said diluted whole blood sample, said predetermined volume of said density gradient solution, and said diameter of said tube; and (e) aspirating a predetermined volume of liquid from said tube using a predetermined relative lateral movement between said aspiration/dispense probe and said tube in order to aspirate said cells of interest from different portions of said cell layer, said predetermined volume being sufficient to (i) drop said cell layer to a level in which said probe port becomes immersed in said cell layer, and (ii) enable said probe port to remain in said cell layer until such said predetermined volume of liquid has been aspirated.