Anti-L6D antibodies enable researchers to detect and measure the L6D antigen in biological samples. This target is a reported synonym of the TM4SF18 gene, which encodes transmembrane 4 L six family member 18. The human version of L6D has a canonical amino acid length of 201 residues and a protein mass of 22.3 kilodaltons. It is reported to be localized in the membrane of cells and notably expressed in the urinary bladder, kidney, and gallbladder. L6D is a member of the L6 tetraspanin protein family.