NOWADAYS, AUTOIMMUNE DISEASES, ARE CONSIDERED AS A MAIN PROBLEM IN MEDICAL COMMUNITIES AND DIAGNOSIS, MANAGEMENTAND TREATMENT OF THESE DISORDERS, ARE VERY IMPORTANT. ANTI NUCLEAR ANTIBODY (ANA) IS ONE OF THE COMMON ASSAYS FORSCREENING OF RHEUMATIC DISEASES WHICH IS DETERMINANT IN DIAGNOSIS OF THESE DISEASES TREATMENT. MATERIALS AND METHOD: THIS STUDY, WAS FORMED DUE TO THE MISCONCEPTION ABOUT ANA TEST, THAT FREQUENTLY IS PERFORMED WITH METHODS BASED UPONSOLID PHASE AS ELISA. THIS EXPERIMENT WAS CONDUCTED ON 215 PATIENTS, WITH CLINICAL SYMPTOMS, THAT ARE LIKELY AFFECTEDWITH RHEUMATIC DISEASES, SIMULTANEOUSLY, BY MEANS OF ANA AND FANA. ...