Magnetic beads for reducing leukocyte interference in immunoassays
First Claim
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1. A cartridge for performing a competitive immunoassay for a sample analyte suspected of being present in a blood sample containing leukocytes, the cartridge comprising:
- a sample inlet for receiving the blood sample;
a metering chamber for metering the blood sample to form a metered sample;
one or more dry reagent coating layers within the cartridge comprising magnetic beads opsonized to leukocytes and a labeled analyte, wherein the opsonized magnetic beads are present in an amount in excess of the leukocytes in the blood sample sufficient to substantially sequester any leukocytes present in the sample;
an electrode comprising an immobilized antibody to the sample analyte and to the labeled analyte; and
one or more pumping elements for moving the metered sample and the labeled analyte to the electrode.
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Abstract
Methods and devices for reducing interference from leukocytes in an analyte immunoassay are provided. In one embodiment, a method is provided comprising the steps of amending a biological sample with magnetic sacrificial beads opsonized to leukocytes, binding leukocytes in the sample to the magnetic sacrificial beads, and magnetically retaining the beads out of contact from an immunosensor.
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Citations
21 Claims
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1. A cartridge for performing a competitive immunoassay for a sample analyte suspected of being present in a blood sample containing leukocytes, the cartridge comprising:
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a sample inlet for receiving the blood sample; a metering chamber for metering the blood sample to form a metered sample; one or more dry reagent coating layers within the cartridge comprising magnetic beads opsonized to leukocytes and a labeled analyte, wherein the opsonized magnetic beads are present in an amount in excess of the leukocytes in the blood sample sufficient to substantially sequester any leukocytes present in the sample; an electrode comprising an immobilized antibody to the sample analyte and to the labeled analyte; and one or more pumping elements for moving the metered sample and the labeled analyte to the electrode. - View Dependent Claims (2)
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3. A cartridge for performing a non-competitive immunoassay for a sample analyte suspected of being present in a blood sample containing leukocytes, the cartridge comprising:
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a sample inlet for receiving the blood sample; a metering chamber for metering the blood sample to form a metered sample; one or more dry reagent coating layers within the cartridge comprising magnetic beads opsonized to leukocytes and a signal antibody to the analyte, wherein the opsonized magnetic beads are present in an amount in excess of the leukocytes in the blood sample sufficient to substantially sequester any leukocytes present in the sample; an electrode comprising an immobilized antibody to the sample analyte; and one or more pumping elements for moving the metered sample to the electrode. - View Dependent Claims (4)
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5. A kit for performing an analyte immunoassay in a whole blood sample, comprising:
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magnetic beads opsonized to leukocytes, wherein the magnetic beads are movable by a magnetic field, and wherein magnetic beads are present in an amount in excess of the leukocytes in the blood sample sufficient to substantially sequester any leukocytes present in the sample; a magnet in the cartridge for retaining the magnetic beads; and an immunosensor, wherein leukocytes in the whole blood sample bind to said magnetic beads, and wherein the magnetic field is capable of retaining at least a portion of said magnetic beads out of contact from said immunosensor. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A cartridge for performing a competitive immunoassay for a sample analyte suspected of being present in a blood sample containing leukocytes, the cartridge comprising:
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a sample inlet for receiving the blood sample; a metering chamber for metering the blood sample to form a metered sample; one or more dry reagent coating layers on the cartridge comprising magnetic beads opsonized to leukocytes and a labeled analyte, wherein the magnetic beads are present in an amount sufficient to provide a dissolved bead concentration of at least 5 micrograms per microliter of sample which is an amount in excess of the leukocytes in the blood sample sufficient to substantially sequester any leukocytes present in the sample; an electrode comprising an immobilized antibody to the sample analyte and to the labeled analyte; and one or more pumping elements for moving the metered sample and the labeled analyte to the electrode. - View Dependent Claims (20, 21)
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Specification