Anti-KRT81 antibodies are used in the immunodetection of the protein keratin 81. In humans, the canonical protein has a reported length of 505 amino acid residues and a mass of 54.9 kDa. It is found to be highly expressed in the differentiating cortex of growing (anagen) hair. The KRT81 protein is a member of the Intermediate filament protein family. Synonyms for this target antigen include Hb-1, K81, KRTHB1, MLN137, ghHkb1, hHAKB2-1, keratin, type II cuticular Hb1, and HB1.