Bayer Corporation

Lynn Paseltiner

David Zelmanovic

Gregory M Colella

Edward J Hetherington

Evelyn Sabrinah Chapman

Martin Sorette

The invention provides a very fast and reliable method and reagent composition for determining reticulocyte and erythrocyte counts, identification and characterization, as well as platelet counts, in a whole blood sample using fully automated hematology analyzers. The reagent composition includes a zwitterionic surfactant as sphering agent for reticulocytes and erythrocytes, an organic cationic dye, e.g., Oxazine 750, for staining the reticulocytes, and buffer solution components for maintaining a reagent pH of about 7.2 to 7.8, and an osmolarity of about 292.+-.5. On the basis of the particular pH, ionic strength, and dye concentration, the reagent composition of the present method improves upon previous methods, thus allowing fully automated blood sample analyses to be completed in less than about 30 seconds, with only about a 20 second incubation of sample in the reagent solution before analysis. With such a rapid incubation time, the reagent mixture is passed through the sensing region of a flow cytometer, and the light scattered and absorbed by each cell is rapidly measured to provide accurate cell determinations and counts. The volume and hemoglobin concentration and content of each erythrocyte or reticulocyte are determined. Mean cell volume, mean corpuscular hemoglobin concentration, and mean cell hemoglobin of the reticulocytes and/or erythrocytes are calculated from the measured cell-by-cell volume and hemoglobin concentration.

Fully automated method and reagent composition therefor for rapid

The present invention provides a highly sensitive and accurate method and system for the discrimination and quantification of platelets in a whole blood sample using automated hematology instruments. The method and system of the invention provide the accurate measurements of platelet dry mass and platelet component concentration in both normal blood samples and in abnormal blood samples, such as those from thrombocytopenic patients. The determination of platelet dry mass and platelet component concentration can serve to assess the activation state of platelets since activated platelets possess measurably lower component concentrations and refractive indices than do non-activated platelets. The method and system of the invention also allows the clinician or skilled practitioner to determine the age of a blood sample on the basis of the measured parameter of platelet component concentration.

Highly sensitive, accurate, and precise automated method and device for

The present invention provides a highly sensitive and accurate method and system for the discrimination and quantification of platelets in a whole blood sample using automated hematology instruments. The method and system of the invention provide the accurate measurements of platelet dry mass and platelet component concentration in both normal blood samples and in abnormal blood samples, such as those from thrombocytopenic patients. The determination of platelet dry mass and platelet component concentration can serve to assess the activation state of platelets since activated platelets possess measurably lower component concentrations and refractive indices than do unactivated platelets. The method and system of the invention also allows the clinician or skilled practitioner to determine the age of a blood sample on the basis of the measured parameter of platelet component concentration.

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Monroe, NY, United States of America

Lynn Paseltiner