Ready-to-use ELISA kits are available for the detection of PBSF/SDF-1, an alias of the protein, C-X-C motif chemokine receptor 4. The official gene symbol is CXCR4. The protein, with a mass of 39.7 kDa and length of 352 residues, is reported to be membrane-associated. It is a member of the G-protein coupled receptor 1 family and may be known by other names, including: fusin, chemokine receptor, SDF-1 receptor, LPS-associated protein 3, CD184 antigen, and C-X-C chemokine receptor type 4, and lipopolysaccharide-associated protein 3.