RA should be evaluated by a rheumatologist – a specialist physician with the skills and experience to accurately diagnose and treat the disease. RA can be challenging to diagnose because the clinical symptoms are not exclusive to RA and may occur in a number of other inflammatory arthropathies. The diagnosis of RA is based on the symptoms, the medical history, the physical examination, an X ray and a blood test.

The four most important investigations are:

• the patient’s medical history
• clinical examination
• blood testing
• radiological imaging

The American College of Rheumatology 1987 classification criteria for RA
are guidelines for diagnosing RA..

1. Morning stiffness (in and around the joints, lasting at least one hour before maximal improvement)
2. Arthritis of three or more joint areas: At least three joint areas simultaneously have had soft tissue swelling or fluid (not bony overgrowth alone) observed by a physician. The 14 possible areas are right or left proximal interphalangeal (PIP) joint, metacarpophalangeal (MCP) joint, wrist, elbow, knee, ankle, and metatarsophalangeal (MTP) joints
3. Arthritis of hand joints: At least one area swollen (as defined above) in a wrist, MCP, or PIP joint
4. Symmetric arthritis: Simultaneous involvement of the same joint areas (as defined in 2) on both sides of the body (bilateral involvement of PIPs, MCPs, or MTPs is acceptable without absolute symmetry)
5. Rheumatoid nodules: Subcutaneous nodules, over bony prominences, or extensor surfaces, or in juxtaarticular regions, observed by a physician
6. Serum rheumatoid factor: Demonstration of abnormal amounts of serum rheumatoid factor by any method for which the result has been positive in <5% of normal control subjects
7. Radiographic changes: Radiographic changes typical of rheumatoid arthritis on posteroanterior hand and wrist radiographs, which must include erosions or unequivocal bony decalcification localized in or most marked adjacent to the involved joints (osteoarthritis changes alone do not qualify)