Rheumatoid arthritis is a chronic, destructive autoimmune disease affecting the joints. With more sophisticated and effective therapies becoming available and with the understanding that early intervention is crucial in preventing irreversible joint damage, it is more and more important to diagnose Rheumatoid arthritis at a very early stage in the disease. To facilitate diagnosis during the early stages of the disease, when often not all clinical symptoms are manifest, a good serological marker is needed. The main purpose of this book was to evaluate and detects a good serological marker and genetic factors may be used in early detection of Rheumatoid arthritis.