Method for the volumetric differentiation of blood cells types

Claim 1

In a method for volumetrically differentiating leukocytes in a whole blood sample into three subpopulations, identified as lymphocyte, neutrophilic granulocyte and infrequent and rare leukocyte subpopulations, using an atomatic particle analyzing system, said method comprising the steps of: (a) supplying a whole blood sample, a volume of diluent suitably balanced for maintaining cell size in the whole blood sample, and a volume of a lysing reagent to an automatic particle analyzing system; (b) mixing the whole blood sample with the diluent and the lysing reagent in the automatic particle analyzing system in such a manner as to enable enumeration of the lymphocyte and neutrophilic granulocyte subpopulations in the whole blood sample and to enable quantitative evaluation of the infrequent and rare leukocyte subpopulation in the whole blood sample; and (c) using the automatic particle analyzing system to enumerate the lymphocyte and neutrophilic granulocyte subpopulations in the whole blood sample and to quantitatively evaluate the infrequent and rare leukocyte subpopulation in the whole blood sample; wherein the improvements comprise: using a diluent containing cell-stabilizing 1,3-dimethylurea and using a lysing agent consisting of 55-150 ml of a 50% (w/v) solution of a single, intrinsically gentle, quaternary ammonium salt, up to 4 g of potassium cyanide, and sufficient water to make one liter, wherein the quaternary ammonium salt is selected from the group consisting of salts having the general formula: ##STR2## wherein R 1 , R 2 and R 3 are short-chain alkyl groups having one to four carbons, R 4 is a twelve-carbon alkyl group, and X is a cation selected from the group consisting of halides, sulfates, nitrates, and phosphates.