Multicentre study to improve clinical interpretation of rheumatoid factor and anti-citrullinated protein/peptide antibodies test results oleh Lieve Van Hoovels, Xavier Bossuyt, Daniel Aletaha, Christopher Sjöwall, Stefanie Van den Bremt, Diego Kyburz, Alf Kastbom, Peggy Jacques, Laura Bogaert, Carolien Bonroy, Bert Vander Cruyssen, Ingmar Heijnen, Patrick Verschueren, Charlotte Dahle, Rille Pullerits, Saša Čučnik, Guenter Steiner, Daniela Sieghart, Eszter Nagy, Luca Bernasconi, Farid Benkhadra, Ann Van Liedekerke, Geert Vanheule, Johan Robbrecht, Lucy Studholme, Claudine Wirth, Rüdiger Müller, Rok Ješe, Boja Jovancevic, Emese Kiss