A newer, more specific blood test for rheumatoid arthritis is the citrulline antibody test.
RA Diagnostic Test: Citrulline Antibody Test
Abnormal blood antibodies can be found in patients with rheumatoid arthritis. A blood antibody called “rheumatoid factor” can be found in 80% of patients. Citrulline antibody is present in most patients with rheumatoid arthritis. It is useful in the diagnosis of rheumatoid arthritis when evaluating patients with unexplained joint inflammation. A test for citrulline antibodies is most helpful in detecting the cause of previously undiagnosed inflammatory arthritis when the traditional blood test for rheumatoid arthritis, rheumatoid factor, is not present. Citrulline antibodies are also indicators of potentially more aggressive disease. Citrulline antibodies have been felt to represent the earlier stages of rheumatoid arthritis in this setting. Another antibody called “the antinuclear antibody” (ANA) is also frequently found in patients with rheumatoid arthritis.