A method for determining an analyte in a sample suspected to comprise said analyte, comprising a) contacting with said sample at least a first and a second capture compound for said analyte, wherein said first and second capture compounds are non-identical capture compounds measurably different in at least one chemical and/or physical property, wherein said capture compounds compete in binding to said analyte, and wherein said capture compounds are polypeptides; b) contacting said capture compounds contacted with said sample with a specifier bonded to an indicator, wherein said specifier competes in binding to said capture compounds with said analyte; c) determining the amount of complexes comprising said specifier and a capture compound; and d) determining said analyte in a sample based on the result of step c), w herein said second capture compound is derived or derivable from said first capture compound by at least one of: (i) introducing at least one amino acid exchange into the amino acid sequence of said first capture compound, (ii) producing said second capture compound in a different cellular background as compared to said first capture compound, (iii) removing or preventing glycosylation of said second capture compound as compared to said first capture compound, (iv) purifying said second capture compound by different means and/or by a different method as compared to said first capture compound, (v) denaturing and/or refolding said second capture compound under different conditions as compared to said first capture compound, and (vi) storing said second capture compound under different conditions as compared to said first capture compound. a) contacting with said sample at least a first and a second capture compound for said analyte, wherein said first and second capture compounds are non-identical capture compounds measurably different in at least one chemical and/or physical property, wherein said capture compounds compete in binding to said analyte, and wherein said capture compounds are polypeptides; b) contacting said capture compounds contacted with said sample with a specifier bonded to an indicator, wherein said specifier competes in binding to said capture compounds with said analyte; c) determining the amount of complexes comprising said specifier and a capture compound; and d) determining said analyte in a sample based on the result of step c), w herein said second capture compound is derived or derivable from said first capture compound by at least one of: (i) introducing at least one amino acid exchange into the amino acid sequence of said first capture compound, (ii) producing said second capture compound in a different cellular background as compared to said first capture compound, (iii) removing or preventing glycosylation of said second capture compound as compared to said first capture compound, (iv) purifying said second capture compound by different means and/or by a different method as compared to said first capture compound, (v) denaturing and/or refolding said second capture compound under different conditions as compared to said first capture compound, and (vi) storing said second capture compound under different conditions as compared to said first capture compound. (i) introducing at least one amino acid exchange into the amino acid sequence of said first capture compound, (ii) producing said second capture compound in a different cellular background as compared to said first capture compound, (iii) removing or preventing glycosylation of said second capture compound as compared to said first capture compound, (iv) purifying said second capture compound by different means and/or by a different method as compared to said first capture compound, (v) denaturing and/or refolding said second capture compound under different conditions as compared to said first capture compound, and (vi) storing said second capture compound under different conditions as compared to said first capture compound.