An Overview of the Intrinsic Role of Citrullination in Autoimmune Disorders

Table 5

Classification criteria for rheumatoid arthritis established by the American College of Rheumatology (ACR) in 1987.

Criteria	Definition
Morning stiffness	Morning stiffness persisting at least 1 hour before maximal progression
Arthritis of 3 or more joint areas	Presence of swelling in three or more joints, including the right or left PIP, MCP, wrist, elbow, knee, ankle, and MTP joints
Arthritis of hand joints	Swelling of one or more of hand joints, including wrist, MCP, or PIP joint
Symmetric arthritis	Concomitant involvement of the same joint areas on both sides of the body
Rheumatoid nodules	Clinical observation of subcutaneous nodules over bony prominences, extensor surfaces, or in juxta-articular bones as seen by a physician
Serum rheumatoid factor	Positive or elevated level of serum rheumatoid factor measured by laboratory method
Radiographic changes	Radiographic changes involve erosions in joint on posteroanterior hand and wrist, also displaying thinning of juxta-articular region