The diseases represented by high rheumatoid factor are mainly rheumatoid arthritis and other connective tissue diseases, as follows: a. Rheumatoid arthritis: most commonly seen in rheumatoid arthritis, patients with rheumatoid arthritis are likely to have elevated rheumatoid factor, but at the same time patients will also have inflammatory indicators, including increased blood sedimentation, C-reactive protein, and positive anti-CCP antibodies. Second, other connective tissue diseases: elevated rheumatoid factor is commonly found in other connective tissue diseases, most commonly dry syndrome and systemic lupus erythematosus, which also show elevated rheumatoid factor. Third, physiological factors and infection factors: rheumatoid factor elevation is seen in some older people, older people will appear physiological rheumatoid factor elevation, while some infectious diseases, such as hepatitis B infection, will also appear rheumatoid factor higher than normal.