Test device for detecting the presence of a residue analyte in a sample

An inhibition-type assay test device for detecting the presence of one or more members of an analyte family, wherein a positive result does not differentiate one particular analyte from another, at reduced sensitivity safe levels in an analyte family, in a sample, which test device comprises:

• a) a support strip;
• b) a sample-absorbing matrix attached to said support strip, said sample-absorbing matrix having material for absorbing an amount of the sample;
• c) a mobile-phase support for holding a mobile-phase composition, said mobile-phase support and mobile-phase composition being in contact with said sample-absorbing matrix;
• d) a mobile-phase composition having a labelled receptor for binding with all of the members of an analyte family and one or more analyte specific antibodies, each analyte specific antibody having a binding affinity for a selected analyte of the analyte family, but not all of the analyte family;
• the analyte specific antibody competing with the labelled receptor to remove a specific analyte from binding to said labelled receptor which is capable of binding to a family of analytes;
• the analyte specific antibodies present in an amount to reduce the test sensitivity for the selected analyte;
• and which analyte specific antibodies do not compete for binding at the test zone or control zone, but pass unreacted through the test zone and control zone toward a disposal zone;
• e) a stationary-phase membrane in contact or contacted with the mobile-phase composition and having a first end and a second end, and wherein said membrane allows lateral capillary flow of the sample from the first end to the second end;
• f) a test zone on the membrane having a first binder bound to said membrane, said first binder bound to said membrane containing an analyte member of the analyte family, to form a first analyte-labelled receptor complex, other than an analyte for which there is provided an analyte specific antibody, and said first binder binding with unbound labelled receptor to provide a detectable signal;
• and
• g) a control zone having a second binder bound to said membrane to bind with said labelled receptor, to provide a signal that the test is complete, and for comparison to the signal of the test zone;
• the test device arranged and constructed to provide a positive or negative result of the safe threshold level of the analyte family present, where each member has a threshold for a positive or negative result, which is different from other members.