Patent ID: 7226749

Claim:
A method for producing an antibody to the N-terminal portion of (1-84) PTH useful in the determination of intact PTH 1-84 levels in a biological sample, the method comprising the steps: a) administering a first peptide antigen to a host animal to induce antibody production against said first peptide antigen in said host animal, said first peptide antigen being selected from the group consisting of SEQ ID NO. 3, SEQ ID NO. 4, SEQ ID NO. 5, SEQ ID NO. 6, (1-34) PTH and (1-84) PTH; b) monitoring antibody titer produced by said administration of said first antigen to said host animal; c) extracting antisera produced in said host animal by said administration of said first peptide antigen; d) isolating and selecting at least one antibody from said antisera extracted in step c) by affinity chromatography utilizing a second peptide antigen selected from the group consisting of SEQ ID NO. 3, SEQ ID NO. 4, SEQ ID NO. 5, and SEQ ID NO.6; e) removing said at least one antibody isolated in step d) having specificity for a peptide antigen selected from the group consisting of (4-34) PTH, (5-34) PTH, (4-84) PTH and (5-84) PTH; and f) isolating said antibody in steps d) and e) having a binding affinity for at most the first three or four amino acid residues of the N-terminal portion of PTH and wherein the isolated antibody has no binding affinity for any amino acid residues at or beyond the fifth amino acid residues of the N-terminal of PTH.