Anti-XK related X-linked antibodies are used for the immunodetection of the protein encoded by the XKRX gene. In humans, the canonical protein has a reported length of 449 amino acid residues and a mass of 52.1 kDa. Its subcellular localization is in the cell membrane. Alternative splicing is reported to yield 2 different isoforms for this protein. It is reported to be highly expressed in the placenta, in syncytiotrophoblasts. It is a member of the XK protein family. Other names for this target antigen include X Kell blood group precursor-related, X-linked, X-linked Kx blood group related, X-linked, XK, Kell blood group complex subunit-related, X-linked, membrane protein XPLAC, and XK-related protein 2. Gene orthologs have been identified in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species. Western Blot is the most common application for the XK related X-linked antibodies listed below. ELISA and Immunohistochemistry are also common applications.