Patent ID: 7438890

Claim:
A method of detecting CEA in a subject comprising the steps of: a) detectably labeling a polypeptide having the ability to bind CEA and comprising the amino acid sequence: Cys-X 4 -X 5 -X 6 -X 7 -X 8-X 9 -X 10-X 11 -Cys, (SEQ ID NO: 110), wherein: X 4 is selected from the group consisting of: Asn, Glu, Asp, and Met; X 5 is selected from the group consisting of: Leu, Phe, Tyr, Trp, Val, Met, Ile, and Asn; X 6 is selected from the group consisting of: Phe, Leu, Asp, Glu, Ala, Ile, Lys, Asn, Ser, Val, Trp, Tyr, Gly, and Thr; X 7 is selected from the group consisting of: Lys, Phe, Asp, Gly, Leu, Asn, Trp, Ala, Gln, and Thr; X 8 is selected from the group consisting of: Asn, Pro, Phe, Gly, Asp, Ala, Ser, Glu, Gln, Trp, His, Arg, Met, Val, and Leu; X 9 is selected from the group consisting of: Gln, Lys, Leu, and Gly; X 10 i is selected from the group consisting of: Trp, Ala, and Tyr; and X 11 is selected from the group consisting of: Phe, Thr, Met, Ser, Ala, Asn, Val, His, Ile, Pro, Trp, Tyr, Gly, Leu, and Glu; b) administering to said subject the labeled polypeptide; and, thereafter, c) detecting the labeled polypeptide in the subject.