Method of using anticoagulant solution in blood separation

A method for separating lymphocytes and monocytes from heavier phases of a sample of whole blood or a pretreated cell fraction thereof, said method comprising the steps of:

• providing a container having an open end a closed end, said container further having a first layer of a thixotropic gel-like substance contained therein at a first position, said container also having an anticoagulant solution for preventing coagulation of said sample when said sample is introduced into said container, said solution located at a second position within said container in closer proximity to said open end of said container than said first layer, said solution having an effective concentration of sodium citrate and pH adjustor to modify the pH of the sodium citrate anticoagulant solution, sufficient for preventing coagulation of said sample when said sample is added to said container, said solution having an adjusted pH ranging from 6.5 to 8.5;
• introducing said sample into said container;
• and
• centrifuging said container to induce separation of lymphocytes and monocytes from heavier phases of said sample, wherein the anticoagulant solution affords more efficient cell separation having reduced red blood cell contamination and enhanced recovery and viability of the separated lymphocytes and monocytes.