Anti-H2AC19 antibodies are used in the immunodetection of the protein H2A clustered histone 19. It is notably widely expressed in many tissue types. Synonyms for this target antigen include histone 2, H2aa4, histone H2A/r, histone cluster 2 H2A family member a4, histone cluster 2, H2aa4, and histone H2A type 2-A. H2AC19 gene orthologs have been reported in the mouse and rat species.