Anti-KRTAP9-4 antibodies are used in the immunodetection of the protein keratin associated protein 9-4. In humans, the canonical protein has a reported length of 154 amino acid residues and a mass of 16.4 kDa. It is a member of the KRTAP type 9 protein family. Synonyms for this target antigen include keratin-associated protein 9.4 and ultrahigh sulfur keratin-associated protein 9.4.