Diagnosis of Rheumatoid Arthritis is based on a combination of clinical presentation, physical examination of affected joints, blood tests and X-ray findings.
Physical examination reveals swelling, tenderness, warmth and deformity (if present) of the affected joints. In some patients, rheumatoid nodules can be seen and felt.
In 2010, the American College of Rheumatology suggested a set of criteria based on which Rheumatoid Arthritis can be diagnosed.
From the criteria given below, at least 4 symptoms from 7 should be present for more than 6 weeks
- Morning stiffness for more than 1 hour
- Soft tissue swelling in any of 3 joint areas simultaneously
- Simultaneous involvement of same joint areas of both sides of the body
- Presence of any subcutaneous nodules over bony prominences or extensor surfaces
- Abnormal serum RA factor
- X-ray changes of Rheumatoid Arthritis in hands and wrists showing erosions and bone decalcification in involved joints.
Other tests includes-
- Complete Blood Count: It detects anaemia along with increase in white blood cell count
- Erythrocyte sedimentation rate (ESR): It is usually elevated in most cases of Rheumatoid Arthritis
- Rheumatoid factor (RA Factor): It is one of the definitive factors to diagnose Rheumatoid Arthritis. A positive RA factor establishes the presence of Rheumatoid Arthritis; however, a negative RA factor does not rule out the disease.
- Anti-Cyclic Citrullinated Peptide (Anti-CCP): This is one of the recent additions and has been found to be more specific than RA Factor to diagnose Rheumatoid Arthritis. It determines the autoimmune basis of the disease.
- X-ray: X-ray of hands and feet are taken for patients with polyarthritis. There are no changes in the initial stage of the disease, but sometimes, soft tissue swelling and loss of joint space can be noticed. As the disease advances, there may be bony erosions and subluxation (partial dislocation).
- Biopsy of Joint Fluid: Extracting fluid present within the affected joint can help to rule out the presence of other joint diseases like Gout and Infection.