Controlled-volume assay apparatus
First Claim
1. A diagnostic apparatus for use in determining the concentration of a selected analyte in a body-fluid sample, comprisingsample dispenser having (i) a support, (ii) a well defined in the support for receiving such sample, (iii) a fibrous filter matrix, (iv) capillary means for drawing sample fluid from said well into the matrix, and (v) an absorbent strip on said support having a central region in fluid contact with said matrix for distributing ample fluid from the matrix by capillary flow to sample-delivery sites in opposite end regions of the strip,a test plate carrying a plurality of wettable, absorbent pads, each having an exposed outer surface region and a defined expanse, said plurality of pads containing reagent means effective to produce a detectable analyte-dependent reaction product for detection of a selected analyte, when sample fluid is transferred from said sample-delivery sites to said plurality of pads, andmeans mounting said plate on said dispenser, said mounting means being adjacent to and spaced from said plurality of pads, for movement toward and away from a sample-delivery position at which substantially the entire outer exposed surface regions of said plurality of pads are in contact with the sample-delivery sites, for simultaneous transfer of substantially the same volume of sample fluid from each of said delivery sites to each of said pads in the support with fluid movement at a substantially uniform flow rate in a direction normal to the pad outer surface regions throughout the entire expanse of each of said pads, whereby said pads are filled uniformly to a selected volume when said pads are held in contact with said sample-delivery sites for a selected period of time, andcontrol means operatively connected to said shifting means for placing said support at its sample-delivery position for such sample-delivery time.
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Accused Products
Abstract
Method and apparatus for use in determining the concentration of a selected analyte in a body-fluid sample. As the fluid sample is applied to a wettable, absorbent reaction pad, the extent of sample wetting of the pad is monitored by surface reflectance. This surface monitoring is used to control the volume of sample applied to the pad, to prevent overfilling the pad and to allow determination of the final sample volume applied. From the known sample volume and amount of analyte, the concentration of analyte in the sample can be accurately calculated in reaction components, trapping agents, matrix configuration, and analyte tested can be made.
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Citations
10 Claims
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1. A diagnostic apparatus for use in determining the concentration of a selected analyte in a body-fluid sample, comprising
sample dispenser having (i) a support, (ii) a well defined in the support for receiving such sample, (iii) a fibrous filter matrix, (iv) capillary means for drawing sample fluid from said well into the matrix, and (v) an absorbent strip on said support having a central region in fluid contact with said matrix for distributing ample fluid from the matrix by capillary flow to sample-delivery sites in opposite end regions of the strip, a test plate carrying a plurality of wettable, absorbent pads, each having an exposed outer surface region and a defined expanse, said plurality of pads containing reagent means effective to produce a detectable analyte-dependent reaction product for detection of a selected analyte, when sample fluid is transferred from said sample-delivery sites to said plurality of pads, and means mounting said plate on said dispenser, said mounting means being adjacent to and spaced from said plurality of pads, for movement toward and away from a sample-delivery position at which substantially the entire outer exposed surface regions of said plurality of pads are in contact with the sample-delivery sites, for simultaneous transfer of substantially the same volume of sample fluid from each of said delivery sites to each of said pads in the support with fluid movement at a substantially uniform flow rate in a direction normal to the pad outer surface regions throughout the entire expanse of each of said pads, whereby said pads are filled uniformly to a selected volume when said pads are held in contact with said sample-delivery sites for a selected period of time, and control means operatively connected to said shifting means for placing said support at its sample-delivery position for such sample-delivery time.
Specification