Sample metering device and assay device with integrated sample dilution

Abstract

In one embodiment, the invention is to a sample metering device, comprising a sample holding chamber oriented between a sample entry port and a sample isolation unit and having a diluent introduction port disposed therebetween for introduction of a diluent into the sample holding chamber. The volume within the sample holding chamber between the diluent introduction port and the sample isolation unit defines a metered volume of a sample for analysis. In another embodiment, the invention is to an apparatus and method for rapid determination of analytes in liquid samples by various assays including immunoassays incorporating a sample dilution feature, preferably suitable for low range sample dilution, and preferably capable of being used in the point-of-care diagnostic field.

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         14 . A method of performing an assay for an analyte in a sample, said method comprising the steps of:
 introducing a sample into a sample chamber of a cartridge, wherein said chamber is located between a sample entry port and a sample isolation unit and includes a diluent introduction port for receiving diluent, and wherein the volume between the diluent introduction port and the sample isolation unit defines a metered volume of said sample for dilution;   transporting a volume of diluent from a diluent conduit to the metered volume of sample, wherein said volume of diluent is combined with said metered volume of sample to form a diluted sample;   transporting said diluted sample to a sensor; and   performing an analyte assay at said sensor.   
     
     
         15 . The method of  claim 14 , wherein the at least one analyte for sensing is CRP. 
     
     
         16 . The method of  claim 14 , wherein the volume of diluent comprises a metered volume of diluent. 
     
     
         17 . The method of  claim 16 , wherein the cartridge includes a pump conduit beginning at a pump and ending at an air introduction port on the diluent conduit, and wherein a region in the diluent conduit between the air introduction port and the diluent introduction port defines the metered volume of diluent. 
     
     
         18 . The method of  claim 14 , wherein the diluted sample is at a dilution ratio of from 1:1 to 50:1 parts by volume diluent:sample. 
     
     
         19 . The method of  claim 14 , further comprising the steps of:
 dissolving a dry reagent into said sample from a wall of the dilution chamber; and   detecting the dry reagent in the diluted sample.   
     
     
         20 . The method of  claim 19 , wherein said dry reagent comprises a lysing agent.