Multipurpose reagent system for rapid lysis of whole blood

A multipurpose reagent system suitable for the automated, multi-part differentiation of white blood cells (WBC), WBC immunophenotyping and the detection of nucleated red blood cells, said multipurpose reagent system concurrently lysing red blood cells and fixing white blood cells in a whole blood sample while preserving WBC membranes and surface antigens, the multipurpose reagent system comprising, in combination:

• from about 3 to about 7 gm/L of a non-quaternary ammonium salt;
• from about 0.04 to about 0.10 percent by volume of a short-chain aliphatic aldehyde;
• from about 10 to about 20 mM of a non-phosphate buffer, said non-phosphate buffer being characterized as substantially inert to said aliphatic aldehyde;
• a WBC membrane and surface active antigen preserving amount of a surface active agent wherein the amount of said surface active agent is from about 10 to about 200 mg/L and
• water, such that said multipurpose reagent system is maintained at a pH between about 5.5 to about 7.5 and an osmolality between about 160 to about 310 mOsm per liter.