266 - L’applicazione di un protocollo combinato per la richiesta e l’esecuzione dei test autoanticorpali migliora l’efficacia clinica nella diagnosi delle malattie reumatiche autoimmuni

The application of a combined protocol for the request and the execution of autoantibodies improves the clinical effectiveness in the diagnosis of the autoimmune rheumatic diseases. Background. The tests of greater meaning for the diagnosis of the autoimmune rheumatic diseases include anti-nuclear antibodies (ANA), anti-extractable nuclear antigens antibodies (ENA) and anti-double stranded DNA antibodies (antidsDNA). As the request of such tests is notably increased in the last years, our objective was to apply a protocol for the appropriate use of laboratory testing according to the most recent international guidelines for the diagnosis of the autoimmune rheumatic diseases, and to appraise the results in terms of clinical effectiveness and economic efficiency. Methods. Beginning from January 2004, a diagnostic protocol was applied for the execution of second level tests (anti- ENA and anti-dsDNA) according to the clinical data supplied on 685 consecutive requests for antibody testing and the results of first level tests (ANA). The patients were then clinically followed for 12 months and the appropriateness of the protocol was evaluated. Results. The introduction of the protocol enabled a significant reduction in the number of second level tests (27.9% vs 49.5% for anti-ENA; 27.5% vs 56.6% for anti-dsDNA). At the end of the follow-up, none of the 163 patients who were negative to first level tests and who had no symptoms of rheumatic disease, to whom second level tests were requested but not performed, were found to be affected by an autoimmune rheumatic disease. Conversely, in 77 of the 85 (90.5%) who were positive to the second level tests, the presence or the development of an autoimmune rheumatic disease was clinically confirmed. Conclusions. ...