What Do Rheumatoid Arthritis Blood Test Results Mean?

Unlike other forms of arthritis, there is a blood screening test available for diagnosing rheumatoid arthritis. This test measures the level of antibody found in the blood of people who are suspected of having rheumatoid arthritis.
  1. Identification

    • The blood test checks for the level rheumatoid factor (RF) antibody. This antibody, according to the University of Maryland Medical Center (UMM), builds up in the lining (synovium) of joints.

    Significance

    • About 80 percent of people with rheumatoid arthritis have elevated RF antibody levels, according to the UMM and Medline Plus.

    Levels

    • Normal levels of RF antibody are reported as less than 40-60 u/mL or less than 1:80 (1 to 80) titer, according to Medline Plus, while elevated RF antibody is higher than these levels.

    Considerations

    • Some people with rheumatoid arthritis do not have elevated RF antibody levels, while some people who do not have rheumatoid arthritis do have elevated levels, according to Medline Plus.

    Features

    • When people have arthritic pain on both sides of the body as well as elevated RF antibody, the UMM reports that aggressive rheumatoid arthritis is a likely diagnosis.

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