Rheumatoid Arthritis (RA) is a common inflammatory form of arthritis that causes pain and swelling of the joints and other organs in the body, such as the lungs and skin. In RA, the immune system attacks healthy tissues, specifically the lining of the joints, causing inflammation and joint damage.
To determine if you have RA or another medical condition your doctor will assess you and may do some investigations including blood tests. Your symptoms and signs on physical examination are more important for making a diagnosis than the results of the tests.
What are blood tests and pathology tests used for?
- Confirming a diagnosis of rheumatoid arthritis or another autoimmune disorder
- Monitoring disease activity and your response to treatment
- Checking for side effects from your medicines
Blood tests commonly used in RA
Erythrocyte Sedimentation Rate (ESR): ESR tests measure the level of inflammation in the body. However, the test does not reflect exactly where in the body the inflammation is or what is causing it. ESR can also be affected by other conditions besides inflammation, so it is used alongside other tests
C-Reactive Protein (CRP): CRP tests measure the level of inflammation in the body by measuring the amount of C-reactive protein in the blood. The test is not specific enough to diagnose a particular type of arthritis or disease, so it is used alongside other tests.
Rheumatoid Factor (RF): The RF test is commonly used to help diagnose rheumatoid arthritis (RA). However, a positive RF test does not always mean a person has RA, as there are several conditions that give positive RF results. Healthy people without RA can also test positive for RF, particularly older people. This does not mean they will develop the condition.
Anti-Cyclic Citrullinated Peptide antibody (anti-CCP): Anti-CCP antibodies (proteins made by the body’s immune system) are commonly present in people with rheumatoid arthritis (RA). This test is useful in the early stages of RA or in borderline cases, as it is a stronger indicator of RA than the rheumatoid factor test. As not all people with early RA test positive, the doctor will use other tests and examinations so the diagnosis is more reliable.
Antinuclear Antibody (ANA): The ANA test is used to screen for autoimmune disorders. A positive ANA test result may suggest an autoimmune disease such as RA, but further testing, along with the patient’s symptoms and signs, is usually needed to make a final diagnosis.
CONTACT YOUR LOCAL ARTHRITIS OFFICE FOR MORE INFORMATION ON ARTHRITIS. For more information about various laboratory tests and how they are used see www.labtestsonline.org.au.