Reagent and method for differential determination of leukocytes in blood

A lytic reagent system, comprising:

• (a) a ethoxylated long chain amine compound represented by the general formula:
• ##STR8## wherein R is an alkyl, alkenyl or alkynyl group having 12 to 22 carbon atoms, m and n are each 1 or more and m+n is between 20 and 40;
• an acid to adjust the pH of the lytic reagent to be within the range of 2.0 to 3.6, and a solubilizer;
• and
• (b) a hypertonic, alkaline stabilizing reagent composition.

A method for stromatolysis of red blood cells in a blood cell sample and analysis of leukocyte subpopulations comprising:

• (a) exposing a blood sample to a lytic reagent composition for a time sufficient to lyse red blood cells, said lytic reagent composition comprising an ethoxylated long chain amine compound represented by the general formula:
• ##STR10## wherein R is an alkyl, alkenyl or alkynyl group having 12 to 22 carbon atoms, m and n are each 1 or more and m+n is between 20 and 40;
• an acid to adjust the pH of the lytic reagent composition to be within the range of 2.0 to 3.6 and a solubilizer;
• (b) adding a hypertonic alkaline stabilizing reagent composition to inhibit the lytic action of the lytic reagent composition;
• and
• (c) analyzing leukocyte subpopulations contained in the blood cell sample.

A method for differentiation of at least four subpopulations of leukocytes in a blood sample comprising:

• (a) analyzing a treated blood sample in a single step measurement by an instrument, wherein said single step measurement is performed with a single aliquot of a blood sample with a lytic reagent composition to obtain at least four subpopulations of leukocytes, wherein said lytic reagent composition comprising an ethoxylated long chain amine compound represented by the general formula:
• ##STR11## wherein R is an alkyl, alkenyl or alkynyl group having 12 to 22 carbon atoms, m and n are each 1 or more and m+n is between 20 and 40;
• an acid to adjust the pH of the lytic reagent composition to be within the range of 2.0 to 3.6 and a solubilizer;
• and wherein the mode of analyzing is selected from at least two members of the group consisting of:
• (1) D.C. volume,
• (2) RF size,
• (3) opacity,
• (4) light scatter, and
• (5) fluorescence
• (b) reporting the results of such analysis in an instrument.