Rheumatoid Factor: Are you seronegative or seropositive?
A blood test, known as rheumatoid factor, is used to help diagnose rheumatoid arthritis. Rheumatoid factor is an immunoglobulin (antibody) which can bind to other antibodies. Antibodies are normal proteins found in the blood which function within the immune system. (Go below to take the poll)
Rheumatoid factor is not normally found in the general population (only found in about 1-2% of healthy people). The incidence of rheumatoid factor increases with age and about 20% of people over 65 years old have an elevated rheumatoid factor. Rheumatoid factor is present in 80% of adults who have rheumatoid arthritis but there is a much lower prevalence in juvenile rheumatoid arthritis. The incidence of rheumatoid factor increases with duration of disease in rheumatoid arthritis: at 3 months the incidence is 33%, while at one year it is 75%. Take our poll: