The present invention provides a specific binding molecule which specifically binds to a peptide having the amino acid sequence of EDGIKRIQDD and comprises a polypeptide having an immunoglobulin VL domain linked to an immunoglobulin VH domain in which the VL domain comprises Complementarity Determining Regions (CDRs) VLCDR1, VLCDR2 and VLCDR3, and in which the VH domain comprises Complementarity Determining Regions (CDRs) VHCDR1, VHCDR2, VHCDR3, each having a respective amino acid sequence as follows in which VHCDR1isGYSFTGYNMN VHCDR2isNIDPYYGGTTYNQKFKG VHCDR3isEVDY VLCDR1isRASKSVSTSTSGYSYMH VLCDR2isLVSNLES VLCDR3isQHIRELTRSEG or an amino acid sequence at least 70% identical thereto.