It’s best to find out for sure if you have this inflammatory form of arthritis, and that will generally require a referral to a rheumatologist. These physicians specialize in the diagnosis and treatment of RA. They have the training and expertise to provide a solid diagnosis in its early stages, when symptoms may closely resemble other forms of arthritis.
To aid in diagnosis, your rheumatologist will perform a number of RA tests, including, in most cases, a rheumatoid factor test. So what tests can help diagnose rheumatoid arthritis, and what is a rheumatoid factor test?
RA Blood Tests
Rheumatologists use several types of blood tests to help diagnose RA. Each looks for specific markers in the blood that can indicate RA. These include certain antibodies, which are chemicals produced by the immune system in response to infection or disease, or certain proteins or other markers that indicate the presence and/or the amount of inflammation in the body.
Rheumatoid Factor Tests
Rheumatoid factor (RF) is an antibody found in the blood of about 80 percent of people with RA. The rheumatoid factor test detects the presence of RF and, when it is present, measures RF levels in the bloodstream.
The presence of RF alone is not a solid confirmation of rheumatoid arthritis, since this antibody is often found in the blood of people who do not have the disease. Nor does the absence of RF in your blood mean that you definitely do not have RA. However, if you do receive a definite RA diagnosis without any finding of RF in your bloodstream, this generally indicates that the course of the disease will be less severe than it might be for someone who tests positive for RF.
Anti-Cyclic Citrullinated Peptide (Anti-CCP) Tests
Anti-cyclic citrullinated peptide (anti-CCP) is an antibody that is present in about 60 to 80 percent of people with RA. The anti-CCP blood test detects these antibodies in the blood. This test is becoming the preferred test for RA, since the anti-CPP antibody is more specific to RA than is the RF antibody.
Anti-Nuclear Antibody Test (ANA)
This blood test detects antibodies that are a general indicator of autoimmune disease. While many RA patients test positive for these antibodies, they are not a definitive indication of RA, since they may be present in other autoimmune/inflammatory conditions.
Erythrocyte Sedimentation Rate (ESR) Tests
ESR is a measure of how quickly red blood cells separate out of the blood, which indicates the degree of inflammation in the body. A high ESR means that high levels of inflammation are present. High ESR, however, is not specific to RA, and can occur with many other conditions.
C-reactive protein (CRP) Tests
CRP is produced by the liver in response to inflammation, and the CRP blood test measures levels of this protein in the body. High levels of CRP indicate significant levels of inflammation. Again, the presence of inflammation alone does not confirm RA.
RA Medical Imaging Tests
Rheumatologists often use medical imaging tests to look for joint damage that can indicate RA. These may include X-rays, which are most helpful in more advanced RA, or MRIs, which can detect the signs of the disease in its earliest stages.
It is important to note that while all of these tests can help your rheumatologist make a diagnosis, no single test can confirm RA on its own. Your doctor will use some combination of these tests, along with a thorough physical exam and evaluation of your symptoms and medical history to ensure an accurate diagnosis.