RHEUMATOID ARTHRITIS – INVESTIGATIONS
The following investigations may be advised to support the diagnosis:
I. Blood tests:
- Total leucocytes count (TLC): Total white blood cell count could be increased.
- Blood haemoglobin levels often show anaemia.
- ESR is usually elevated in almost all the patients.
- Serological tests:
- Rheumatoid factor is present in blood of approximately 75% patients. However, this is not very typical of rheumatoid arthritis as it may be positive in healthy individuals, tuberculosis, leprosy, syphilis, malaria.
- Anti Nuclear Antibodies (ANA) may be seen in rheumatoid arthritis.
II. Synovial fluid analysis: The Synovial fluid analysis for cells, protein and glucose may show evidence of inflammatory arthritis and may support the diagnosis of rheumatoid arthritis.
III. X-ray: X-ray during the early stage usually does not show any change but as the disease progresses the joint space is decreased and degenerative changes can be seen in the cartilage and bone.
The diagnosis of rheumatoid arthritis is made on the basis of characteristic signs and symptoms, supported by laboratory investigations. American Rheumatism Association revised criteria (1987) is sensitive and specific for diagnosing rheumatoid arthritis. At least four of the following features should be present for at least 6 weeks for the condition to qualify as rheumatoid arthritis. Criteria 2-7 must be observed by the doctor.
- Morning stiffness in joint for more than one hour.
- Arthritis of three or more joint area at a time.
- Arthritis of joints of the hand
- Symmetrical arthritis
- Presence of Rheumatoid nodule
- Positive rheumatoid factor
- Radiographic changes