Multiple Assay Device

Abstract

Disclosed is an assay device for the determination of analyte in a liquid sample over an extended concentration range comprising a first assay and a second assay, wherein the first assay for an analyte comprises a first flow-path having a sole detection zone capable of immobilising a labelled binding reagent and the second assay for said analyte comprises a second flow-path having a sole detection zone capable of immobilising a labelled binding reagent, wherein the presence of labelled binding reagent at the detection zones provides an indication of the presence and/or extent of analyte in said liquid sample.

1 . An assay device for determining the presence or concentration of an analyte in a liquid sample over an extended concentration range comprising a first flow-path having a sole detection zone capable of immobilising a labelled binding reagent and a second flow-path having a sole detection zone capable of immobilising a labelled binding reagent, wherein the presence of labelled binding reagent at the detection zones provides an indication of the presence or concentration of analyte in said liquid sample. 
     
     
         2 . The device according to  claim 1  wherein the first flow-path is capable of providing an indication of the level of analyte in a first concentration range and the second flow-path is capable of providing an indication of the level of analyte in a second concentration range. 
     
     
         3 . The device according to  claim 2  wherein the first and second concentration ranges overlap. 
     
     
         4 . The assay device according to  claim 2  which is capable of providing an indication of the level of analyte with respect to one or more thresholds. 
     
     
         5 . The device according to  claim 1  wherein the first and/or second flow-path comprises a porous carrier. 
     
     
         6 . The device according to  claim 5  wherein the porous carrier is a lateral flow porous carrier. 
     
     
         7 . The device according to  claim 1  wherein the first and/or second flow-path comprises a mobilisable labelled binding reagent for the analyte provided upstream from a detection zone. 
     
     
         8 . The device according to  claim 1  wherein the detection zone of the first and/or second flow-path comprises an immobilised binding reagent for the analyte. 
     
     
         9 . The device according to  claim 1  wherein the first flow-path defines a sandwich assay and the second flow-path defines a competition or inhibition assay. 
     
     
         10 . The device according to  claim 9  wherein the first flow-path comprises a mobilisable labelled binding reagent for the analyte provided upstream from a detection zone, said detection zone comprising an immobilised binding reagent for the analyte and wherein the second flow-path comprises a mobilisable binding reagent for the analyte provided upstream from provided upstream from a detection zone, said detection zone comprising an immobilised analyte or analyte analogue for the mobilisable binding reagent. 
     
     
         11 . The device according to  claim 9  wherein the first flow-path comprises a mobilisable labelled binding reagent for the analyte provided upstream from a detection zone, said detection zone comprising an immobilised binding reagent for the analyte and wherein the second flow-path comprises a mobilisable labelled analyte or analyte analogue provided upstream from an immobilised binding reagent for the analyte. 
     
     
         12 . The device according to  claim 9  wherein the first flow-path defines a high analyte sensitivity assay and the second flow-path defines a low analyte sensitivity assay. 
     
     
         13 . The device according to  claim 1  wherein the first flow-path comprises a mobilisable labelled binding reagent for an analyte provided upstream from a detection zone, wherein the detection zone comprises an immobilised non-labelled binding reagent for the analyte; and wherein the second assay comprises a mobilisable labelled binding reagent for a first binding region of the analyte and a scavenger binding reagent for the analyte provided upstream from a detection zone, wherein said detection zone is capable of binding the labelled binding reagent. 
     
     
         14 . The device according to  claim 13  wherein the detection zone of the first or second flow-path comprises an immobilised binding reagent for the analyte. 
     
     
         15 . The device according to  claim 13  wherein the scavenger binding reagent of the second flow-path has a higher affinity for the analyte than the mobilisable labelled binding reagent. 
     
     
         16 . The device according to  claim 13  wherein the mobilisable labelled binding reagent and the scavenger binding reagent of the second flow-path are for respectively a first and second binding region of the analyte, the detection zone comprising an immobilised binding reagent for a second binding region of the analyte. 
     
     
         17 . The device according to  claim 13  wherein the mobilisable labelled binding reagent and the scavenger binding reagent of the second assay are provided in the same region. 
     
     
         18 . The device according to  claim 13  wherein the scavenger binding reagent is provided in a mobilisable form. 
     
     
         19 . The device according to  claim 13  wherein the mobilisable binding reagents and the scavenger reagent are provided on or in a first porous carrier material and the immobilised binding reagent provided at the detection zone is provided on and/or in a second porous carrier material. 
     
     
         20 . The device according to  claim 19  wherein the first porous carrier material is glass-fibre and the second porous carrier material is nitrocellulose. 
     
     
         21 . The device according to  claim 1  wherein the analyte is hCG. 
     
     
         22 . The device according to  claim 16  wherein the first binding region of hCG is the alpha sub-unit and the second binding region is the beta sub-unit. 
     
     
         23 . The device according to  claim 1  wherein the binding reagents are antibodies. 
     
     
         24 . The device according to  claim 1  wherein the fluid sample is urine. 
     
     
         25 . The device according to  claim 1  wherein the binding reagent is labelled with an optically detectable particle. 
     
     
         26 . The device according to  claim 25  wherein the optically detectable particle is a coloured polymer label. 
     
     
         27 . The device according to  claim 1 , comprising a common sample application region which serves to supply liquid sample to both flow-paths. 
     
     
         28 . The device according to  claim 1 , comprising a housing wherein the first and second assays are provided within said housing. 
     
     
         29 . An assay device for determining the presence or concentration of an analyte in a liquid sample comprising a first flow-path and a second flow-path wherein said first flow-path comprises a porous carrier having a detection zone comprising an immobilised binding reagent for an analyte and provided upstream from the detection zone is a mobilisable labelled binding reagent for said analyte; and wherein said second flow-path comprises a detection zone comprising an immobilised binding reagent for the analyte and a mobilisable labelled binding reagent upstream from the detection zone for the analyte and a scavenger reagent for said analyte, wherein detection of the presence of labelled binding reagent at the detection zone provides an indication of the presence or concentration of analyte in said liquid sample. 
     
     
         30 . The assay device according to  claim 29  wherein the first flow-path defines a high sensitivity assay and the second flow-path defines a low analyte sensitivity assay. 
     
     
         31 . The assay device according to  claim 29 , wherein the analyte is hCG. 
     
     
         32 . The device according to  claim 21 , wherein:
 a) the first flow-path is capable of providing an indication of the level of hCG in the sample in a first range of less than or equal to a first threshold; and   b) the second flow-path is capable of providing an indication of the level of hCG in the sample in a second range of above or equal to a second threshold; and   c) the first and second flow-paths together are capable of providing an indication of the level of hCG in a third range of greater than the first threshold but less than the second threshold.   
     
     
         33 . The device according to  claim 29  wherein the scavenger binding reagent has a higher affinity for the analyte than the mobilisable labelled binding reagent. 
     
     
         34 . The device of  claim 32  wherein the first flow-path is capable of providing a positive or negative indication of pregnancy, based upon whether the level of hCG detected in the sample is respectively above or below a base threshold. 
     
     
         35 . An assay kit for determining the presence or concentration of an analyte in a liquid sample comprising an assay device comprising a first flow-path and a second flow-path wherein:
 a) said first flow-path comprises:
 i) a porous carrier having a detection zone comprising an immobilised binding reagent for an analyte; and 
   ii) a mobilisable labelled binding reagent for said analyte upstream from the detection zone; and   b) said second flow-path comprises:
 i) a detection zone comprising an immobilised binding reagent for the analyte; and 
 ii) a mobilisable labelled binding reagent for the analyte and a scavenger reagent for said analyte upstream from the detection zone, 
   
       wherein detection of the presence of labelled binding reagent at the detection zones provides an indication of the presence and/or extent of the analyte in the sample. 
     
     
         36 . A method of fabricating an assay device to reduce a hook effect, wherein the assay device comprises a first flow-path and a second flow-path, comprising the steps of:
 a) providing a first flow-path comprising a porous carrier and a second flow-path comprising a porous carrier;   b) contacting the first flow-path with a first material so as to form a first zone; and   c) contacting the second flow-path with a first material so as to form a second zone, wherein the first zone and the second zone are separated by a distance of at least about 5 mm, and whereby the hook effect is thereby reduced.   
     
     
         37 . The method of  claim 36 , wherein the first material comprises a particulate material. 
     
     
         38 . The method of  claim 37 , wherein the particulate material comprises latex.