Wertigkeit von Anti-Citrullin-Antikörpern in der rheumatologischen Diagnostik

A comparison of methods of three different immunoassays for the proof of anti – citrullin antibodies in the rheumatoid diagnosis Greiner A, Kellner H, Plischke H, Schattenkirchner M, Gruber R Rheumazentrum München, Klinikum der Universität, Medizinische Poliklinik – Innenstadt Background: Up to now the rheumatoid factor was the most sensitive and most specific laboratory method in the diagnosis of rheumatoid arthritis (RA). By the detection of the antibodies against citrullinated peptide with the help of the newly developed ELISA – Systems a more sensitive and specific test in the field of differential diagnosis of RA has been made available. In this study three different anti – CCP – tests have been examined concerning their value in the comparison of the rheumatoid factor and concerning the clinical diagnosis of the RA. Methods: Sera of 275 rheumatoid patients who get outdoor treatment were examined for anti – CCP – antibodies with three different conventional (commercially accessible) ELISAs (EUROIMMUN, INNOVA, GENERIC ASSAYS). For 93 patients the clinical diagnosis was made through the ACR – criteria. This group included all who will surely and probably get the RA – disease. The evaluation among the single tests and in comparison to the rheumatoid factor was determined. Results: A comparison of the single tests among themselves showed the following sensitivity and specificity: GA: 81,2% / 97,9% , EUROIMMUN: 79,6% / 98,3% , INNOVA: 77,5% / 99,4%. All three CCP – tests are more sensitive and specific compared to the rheumatoid factor (73,1%/91,6%). In the calculation of the sensitivity for surly and probably affected persons with RA the following results appeared: GA: sure: 89,2% / probably 55,0%, EUROIMMUN 87,3% / 54,5%, INOVA 86,6% / 52,4%, rheumatoid factor: 81,4% / 47,6%. Conclusion: There were no significant differences of the sensitivity and the specificity of the 3 CCP – tests concerning the rheumatoid factor but also among the single CCP – tests. The sensitivities of the surly predicted diseases was significantly higher compared to the probable diagnosis RA