The aim of the present study was to evaluate the diagnostic yield of three ELISA tests based on this CFFCP1 peptide and two new synthetic chimeric fibrin/filaggrin peptides (CFFCP2, CFFCP3) and to compare their sensitivity and specificity in RA and other disease groups with the commercial CCP2 test. This evidence concerns the gene AGBL2 and rheumatoid arthritis.