Tests for Rheumatoid Arthritis

What are the Tests for Rheumatoid Arthritis?

Arthritis includes a group of conditions that affects joints and can be disabling in the later stages. Arthritis arises due to a variety of causes. Rheumatoid arthritis, is a condition that arises due to an autoimmune reaction, where the body produces antibodies or certain proteins that act against the joint tissues and result in inflammation. Rheumatoid arthritis is more common in women. Diagnosis of rheumatoid arthritis is made based on certain criteria that include clinical features, imaging and blood tests.

An interview with the patient where the patient may complain of:

• Joint pain. Smaller joints are affected in rheumatoid arthritis first, followed by larger joints. The joint involvement is usually symmetrical on both sides of the body
• Morning stiffness
• Joint deformities in later stages

An examination of the patient, which may reveal:

• Swelling and tenderness of the affected joints
• Presence of joint nodules

Common diagnostic tests used in arthritis are:

Imaging tests: They are used to study joint disease. Some of the imaging tests used for rheumatoid arthritis include:

• X-ray: These may not show any changes in the initial stages of rheumatoid arthritis. The joints may show the presence of erosion with reduced joint space and presence of deformity. Features of osteoporosis may be present in the bones adjacent to the affected joints. X-ray is a cheap diagnostic method, but cannot detect very early changes of rheumatoid arthritis.

• Other tests: Other imaging studies like MRI, ultrasound and CT scan can also detect changes in joints in rheumatoid arthritis, but are not used routinely for this purpose.
• Blood tests: Since rheumatoid arthritis is an autoimmune disease, proteins called antibodies can be detected in the blood, which move to the joint, thereby causing arthritis. There are several blood tests that can diagnose the presence of rheumatoid arthritis. The proteins that are looked for in these tests are referred to as markers of the disease. Measurements of several of these markers have been explored for the diagnosis of rheumatoid arthritis. The most commonly used among these are:

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• Rheumatoid factor: This is an antibody often present in the blood of patients with rheumatoid arthritis; a positive test in a patient with symptoms of rheumatoid arthritis confirms the diagnosis. A very high level may indicate a more severe disease. However, rheumatoid factor may also be positive in people who do not suffer from rheumatoid arthritis, therefore caution is required while interpreting a result with positive rheumatoid factor.
• Anti-CCP antibodies: Antibodies to cyclic citrullinated peptides are yet another type of antibodies that help in confirming the diagnosis in patients with positive rheumatoid factor. The test is sometimes positive several years before the appearance of symptoms of rheumatoid arthritis.
• Complete Blood counts: A red blood cell count can help to detect anemia, which is often present in patients with rheumatoid arthritis. A white blood cell count may also be used to aid in the diagnosis.
• Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP): These are blood tests that indicate the presence of inflammation in the body. They can also be used to monitor the response of the patient to treatment.