Patent ID: 7718384

Claim:
A method for determining the concentration of a sErbB3 in a biological sample from a mammal, wherein the sErbB3 consists of SEQ ID NO:2, SEQ ID NO:4, SEQ ID NO:6, or SEQ ID NO:8, the method comprising: a) obtaining a biological sample from the mammal; b) contacting an amount of a first purified antibody that specifically reacts with a first epitope of the sErbB3 in the biological sample to be tested, wherein the first purified antibody is modified with a first labeling moiety; c) contacting the biological sample with an amount of a second purified antibody that specifically reacts with a second epitope of the sErbB3, wherein the second purified antibody is modified with a second labeling moiety, and wherein the second purified antibody does not competitively inhibit the binding of the first purified antibody; and d) detecting the co-presence of the first and second antibodies to determine the concentration of the sErbB3, wherein the first or second epitope of the sErbB3 comprises the sErbB3 unique carboxy terminal region amino acid residues 539-562 of SEQ ID NO: 2, amino acid residues 330-331 of SEQ ID NO: 4, amino acid residues 494-534 of SEQ ID NO: 6, or amino acid residues 371-400 of SEQ ID NO: 8.