Anti-PTX1 antibodies enable researchers to detect and measure the PTX1 antigen in biological samples. This target is a reported synonym of the CRP gene, which encodes C-reactive protein. This protein is known to function in inflammatory response pathways and innate immune responses, among other biological roles. The human version of PTX1 has a canonical amino acid length of 224 residues and a protein mass of 25 kilodaltons, although 2 isoforms have been identified. It is reported to be a secreted protein that is notably expressed in the liver. PTX1 is a member of the Pentraxin protein family.