Immunological Test Element with Improved Control Zone

Abstract

The invention concerns a test element for carrying out an immunological sandwich test for determining an analyte from a liquid sample containing a reagent zone or conjugate zone which contains a conjugate of an analyte binding partner and a label which can be detected directly or indirectly by visual, optical or electrochemical means (e.g., an enzyme, fluorescent or direct label, etc.) wherein the conjugate can be dissolved by the liquid sample, a detection zone which contains a permanently immobilized (i.e., which cannot be detached by the liquid sample) binding partner for the analyte or for complexes containing the analyte; and a control zone which contains a permanently immobilized binding partner for the conjugate of analyte binding partner and label characterized in that the control zone additionally contains one or more permanently immobilized binding partner(s) for the analyte or for complexes containing the analyte.

1 . A test element for carrying out an immunological sandwich test for determining an analyte in a liquid sample comprising:
 a reagent zone comprising (1) a labeled conjugate comprising an analyte binding partner and a label and (2) a tagged conjugate comprising an analyte binding partner and a tagging substance;   a detection zone comprising a permanently immobilized binding partner for the tagging substance; and   a control zone comprising a permanently immobilized binding partner for the tagging substance and a permanently immobilized binding partner for the labeled conjugate.   
     
     
         2 . A method for detecting an analyte from a liquid sample comprising: applying a sample, to a test element according to  claim 1 ; complexing the analyte present in the sample with the labeled conjugate and the tagged conjugate to form an analyte-conjugate complex; binding the analyte-conjugate complex to the permanently immobilized binding partner for the tagging substance in the detection zone; binding the labeled conjugate that has not reacted with the analyte to the permanently immobilized binding partner for the labeled conjugate in the control zone, and binding the analyte-conjugate complex to the permanently immobilized binding partner for the tagging substance in the control zone. 
     
     
         3 . The test element according to  claim 1 , wherein the permanently immobilized binding partners for the tagging substance are the same in the detection zone and in the control zone. 
     
     
         4 . The test element according to  claim 1 , wherein the permanently immobilized binding partner for the tagging substance in the detection zone is streptavidin or polystreptavidin and the permanently immobilized binding partner for the tagging substance in the control zone is streptavidin or polystreptavidin. 
     
     
         5 . The test element according to  claim 1 , wherein the permanently immobilized binding partner for the tagging substance in the detection zone is selected from streptavidin or polystreptavidin. 
     
     
         6 . The test element according to  claim 1 , wherein the permanently immobilized binding partner for the conjugate of analyte binding partner and label in the control zone is a polyhapten. 
     
     
         7 . The test element according to  claim 1 , wherein the permanently immobilized binding partners in the control zone are selected from the group consisting of antigens, haptens or polyhaptens; and streptavidin or polystreptavidin. 
     
     
         8 . The test element according to  claim 1 , wherein the tagging substance is biotin or digoxigenin. 
     
     
         9 . The test element according to  claim 1 , wherein the tagging substance can be used to immobilize a sandwich complex consisting of labeled conjugate, analyte and tagged conjugate in the detection and/or control zone. 
     
     
         10 . The test element according to  claim 1 , wherein the label can be detected by visual, optical or electrochemical means. 
     
     
         11 . A test element for indirectly detecting an analyte in a liquid sample comprising:
 a reagent zone comprising conjugates for complexing with the analyte comprising (1) a first conjugate comprising an analyte binding partner and a label, and (2) a second conjugate comprising an analyte binding partner and a second binding substance;   a detection zone comprising a permanently immobilized binding partner for complexes of the first conjugate, the second conjugate and the analyte; and   a control zone comprising a permanently immobilized binding partner for the first conjugate and the permanently immobilized binding partner for the complexes.