RA Factor helps with the diagnosis of Rheumatoid arthritis which is a systemic disease, meaning it affects the entire body. It is a chronic disease, in which various joints in the body are inflamed, leading to swelling, pain, stiffness, and the possible loss of function. The inflammatory process can also occur in other parts of the body. Inflammation is a byproduct of the body's immune system, which fights infection and heals injuries.