Patent ID: 6303390
Filing Date: 2001-10-16
Classification: G01N,Y10S,Y10T

Abstract:
An improved method for assaying an analyte in a sample, wherein the analyte is selected from the group consisting of a blood group antigen present on erythrocytes and an antibody that binds to a blood group antigen present on erythrocytes;wherein the method comprises treating the sample present in a liquid in an incubation zone of a reaction vessel with a reagent containing an analyte binding partner, wherein the analyte binding partner, in the case where the analyte is a blood group antigen present on erythrocytes is an antibody that binds to the blood group antigen, and in the case where the analyte is an antibody that binds to a blood group antigen present on erythrocytes is the blood group antigen present on erythrocytes;wherein the reaction vessel comprises an incubation zone, an immobilization zone and a collection zone; and wherein a complex of blood group antigen present on erythrocytes and antibody bound thereto is formed in the incubation zone if the reagent contains an antibody that binds to the blood group antigen present in the sample, or if the sample contains an antibody that binds to a blood group antigen present in the reagent;wherein the method further comprises separating the complex, from unbound erythrocytes that have not formed a complex, and detecting the result;wherein the improvement comprises separating the erythrocytes, whether in the form of a complex or unbound, into a separation medium, the separation medium having a density higher than the density of the liquid containing the sample, but lower than the density of erythrocytes;whereby the erythrocytes pass into the separation medium and the antibodies that are not bound to an erythrocyte remain in the liquid containing the sample in the incubation zone;wherein the complex is separated from the unbound erythrocytes by binding the complex to an immunoglobulin-binding substance immobilized in an immobilization zone of the reaction vessel and discharging the unbound erythrocytes to a collection zone of the reaction vessel; and eitherdetecting the erythrocytes in the immobilization zone or the erythrocytes in the collection zone; ordetecting the erythrocytes in each of the immobilization zone and the collection zone.