1987 American College of Rheumatology (ACR) Definition of Rheumatoid Arthritis

A person needs to have 4 out of the 7 criteria listed here to have RA by this definition:

  • morning stiffness that lasts for at least an hour
  • arthritis of 3 or more joints, arthritis of the hand joints
  • symmetric arthritis (that is, the same joints on both sides of the body are affected)
  • rheumatoid nodules (a spot of concentrated swelling or that feels hard under the skin)
  • serum rheumatoid factor (see rheumatoid factor below, serum is just one part of the blood that is separated when you give blood)
  • radiographic (that is, x-ray) changes of the hands or wrists (that is, changes from normal that are seen in x-rays).