Anti-FAM221B antibodies are used in the immunodetection of the protein family with sequence similarity 221 member B. In humans, the canonical protein has a reported length of 402 amino acid residues and a mass of 45.4 kDa. Up to 3 different isoforms have been reported for this protein. It is notably expressed in the testis. It is a member of the FAM221 protein family. Synonyms for this target antigen include protein FAM221B and uncharacterized protein C9orf128. FAM221B gene orthologs have been reported in the mouse, rat, bovine and chimpanzee species. These FAM221B antibodies are widely used in Western Blot experiments, among other applications.