Method for plasma separation and measurement
First Claim
1. A method for transferring measured amounts of plasma from unmeasured blood samples to a test substrate, said method comprisingapplying a volume of whole blood to an absorptive element through a filter member, said absorptive element on a surface of a test substrate, wherein (a) the filter member permits the passage of plasma and plasma macromolecules but inhibits the passage of blood cells and (b) blood cells are retained on the filter member;
- removing the filter member from the absorptive element to separate excess blood and blood cells from the measured amount of plasma absorbed in the absorptive element; and
transferring plasma from the absorptive element to a reaction zone on the surface of the test substrate.
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Abstract
The system for transferring plasma to a test substrate comprises an applicator and the test substrate. The applicator includes a blood reservoir and a filter element which separates cellular components from the blood as plasma is passed to the test substrate. The test substrate includes an absorptive element which receives the plasma from the applicator. In one embodiment, measured amounts of plasma are transferred when the absorptive element becomes saturated, thus stopping the flow of plasma. In another embodiment, excess blood and cellular components are removed from the measured plasma by disengaging the applicator from the test substrate. In another embodiment, plasma transferred to the absorptive element is eluted from the absorptive element by subsequent application of an elution medium.
44 Citations
16 Claims
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1. A method for transferring measured amounts of plasma from unmeasured blood samples to a test substrate, said method comprising
applying a volume of whole blood to an absorptive element through a filter member, said absorptive element on a surface of a test substrate, wherein (a) the filter member permits the passage of plasma and plasma macromolecules but inhibits the passage of blood cells and (b) blood cells are retained on the filter member; -
removing the filter member from the absorptive element to separate excess blood and blood cells from the measured amount of plasma absorbed in the absorptive element; and transferring plasma from the absorptive element to a reaction zone on the surface of the test substrate. - View Dependent Claims (2, 3, 4, 5)
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6. A method for transferring measured amounts of plasma from unmeasured blood samples to an absorptive element on a test substrate, said method comprising:
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applying a volume of whole blood to an absorptive element through a filter member, wherein (a) the absorptive element has a plasma capacity which is less than the amount of plasma in the whole blood volume so that said absorptive element becomes saturated with a predetermined amount of plasma, (b) the filter member permits the passage of plasma and plasma macromolecules but inhibits the passage of blood cells, and (c) excess blood and blood cells are retained on the filter member; and removing the filter member from the absorptive element to separate excess blood and blood cells from the measured amount of plasma absorbed in the absorptive element. - View Dependent Claims (7, 8, 9)
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10. A method for transferring measured amounts of plasma from unmeasured blood samples to an absorptive element on a test substrate, said method comprising:
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applying a volume of whole blood to an absorptive element through a filter member, wherein (a) the filter member permits the passage of plasma and plasma macromolecules but inhibits the passage of blood cells, and (b) blood cells are retained on the filter member; and removing the filter member from the absorptive element to separate excess blood and blood cells from the measured amount of plasma absorbed in the absorptive element. - View Dependent Claims (11, 12, 13)
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14. A method for transferring measured amounts of plasma from whole blood to a test substrate, said method comprising:
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drawing blood through a capillary tube into a reservoir in an applicator; contacting a filter member extending across a transfer port in the applicator adjacent to the reservoir against a contact surface on an absorptive element on the test substrate, wherein (a) the absorptive element has a plasma capacity which is less than the amount of plasma in the blood, in the reservoir, (b) the filter member permits the passage of plasma and plasma macromolecules but inhibits the passage of blood cells, and (c) excess blood and blood cells are retained on the filter member; and removing the filter member from the absorptive element to separate excess blood and blood cells from the measured amount of plasma absorbed in the absorptive element. - View Dependent Claims (15, 16)
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Specification