Method for assaying a target analyte while reducing interference in an immunosensor system

A method for assaying a target analyte while reducing interference in an immunosensor system, comprising:

• contacting a sample containing a target analyte plus an endogenous or exogenous protein, which is not the target analyte, with an immunosensor system comprising
• a first immunosensor that generates a signal based on the formation of a sandwich between an immobilized antibody, a target analyte and a labeled antibody, wherein a portion of the signal arises from a degree of non-specific binding of the labeled antibody in the region of the first immunosensor,
• a second immunosensor that acts as an immuno-reference sensor and generates a signal that is the same as or predictably related to the degree of non-specific binding which occurs in the region of the first immunosensor, and has an immunocomplex between an immobilized antibody and said endogenous or exogenous protein,
• washing said first and second immunosensors with a wash fluid, and
• using a subtraction analyzer, the signal from the first immunosensor, and the signal from the second immunosensor to determine a corrected analyte concentration in the sample.