Abstract: This application provides an antibody or antigen-binding fragment thereof that binds to thyroglobulin, including: a heavy chain variable region having: CDR-H1 having an amino acid sequence selected from SEQ ID NOs: 1, 7, 13, 19, 25, 31, and variants thereof, CDR-1-12 having an amino acid sequence selected from SEQ ID NOs: 2, 8, 14, 20, 26, 32, and variants thereof, and CDR-H3 having an amino acid sequence selected from SEQ ID NOs: 3, 9, 15, 21, 27, 33, and variants thereof; and a light chain variable region having: CDR-L1 having an amino acid sequence selected from SEQ ID NOs: 4, 10, 16, 22, 28, 34, and variants thereof, CDR-L2 having an amino acid sequence selected from SEQ ID NOs: 5, 11, 17, 23, 29, 35, and variants thereof, and CDR-L3 having an amino acid sequence selected from SEQ ID NOs: 6, 12, 18, 24, 30, 36, and variants thereof.