ANPEG-1 is a mouse monoclonal IgM antibody developed using a linear 40 kDa PEG polymer immunogen. It has been used as a positive control antibody in double-bridging immunogenicity assays in both ELISA and LFA formats. ANPEG-1 can be used as either a capture or detector in ELISA-based PK assays. ANPEG-1 recognizes PEG polymers of various lengths and with various terminal functions. It is specific to the PEG structure and does not require a unique terminal function such as an aldehyde, an amine, or a methoxy group on the polymer for antigen recognition.