Any of a group of autoantibodies that are present in the blood of many people with rheumatoid arthritis.
- ‘More than 70 percent of people with the disease produce this factor, which is an antibody to other antibodies, but people with inflammatory diseases other than rheumatoid arthritis also frequently have rheumatoid factor in their blood.’
- ‘A rheumatoid factor and antinuclear antibodies test were negative.’
- ‘A number of classes of endogenous antibodies, including heterophile, rheumatoid factor, and autoantibodies, can interfere with immunoassay measurements of many different analytes.’
- ‘Be aware that a positive rheumatoid factor is only one criterion, and a positive rheumatoid factor need not be present for a diagnosis of RA to be made.’
- ‘Your doctor may try to look for an alternative diagnosis to reactive arthritis by performing rheumatoid factor and anti-nuclear antibody tests.’