Patent ID: 6468732
Filing Date: 2002-10-22
Classification: A01N,Y10T

Abstract:
A method of reversing or reducing aeration induced cell shrinkage and storage induced swelling of cells in a whole blood sample to be analyzed on a hematology analyzer, comprising:a) mixing an analyzable portion of the blood sample with a reagent diluent composition comprising (i) bicarbonate in an amount of about 1.4 to about 35 mmole/L to provide bicarbonate to the diluted sample to match the bicarbonate concentration in venous whole blood and (ii) a surfactant in an amount of about 7.5 to about 8.5 mg/L to sphere blood cells in the sample, and having a pH of about 7.2 to about 7.5, to produce a reagent mixture; said reagent diluent composition being stored prior to use in an air-impermeable container comprised of a flexible collapsible multilayer material that is impermeable to diffusion of carbon dioxide, whereby the bicarbonate concentration and reagent diluent pH are maintained over time in said air-impermeable container, said container being attachable to the hematology analyzer; and b) analyzing the reagent mixture of (a) on the hematology analyzer, whereby the aeration induced cell shrinkage and the storage induced swelling of blood cells mixed with said reagent diluent composition are reversed or reduced; wherein aeration induced cell shrinkage is established by measuring mean cell volume (MCV), and said reagent diluent composition stored in said air impermeable container reverses the effect of blood sample aeration on mean cell volume (MCV) by 100% at room temperature; and further wherein said reagent diluent composition stored in said air-impermeable container reverses about 50% of swelling of a blood sample stored overnight at room temperature.