Anti-O is anti-hemolytic streptococcal element O and RF is rheumatoid factor. Anti-O + RF can be used to check for rheumatoid arthritis. Anti-O is an important reference for rheumatic fever. Elevated anti-O indicates a recent hemolytic streptococcal infection, such as tonsillitis, pharyngitis, scarlet fever and other diseases. Rheumatoid arthritis is associated with streptococcal infections, and the anti-“O” will be elevated. RF, Rheumatoid Factor, is one of the most important serologic criteria for the diagnosis of rheumatoid arthritis.RF has a certain false-positive rate, which can be seen in autoimmune diseases, such as dry syndrome, systemic lupus erythematosus, etc. It can also be seen in infectious diseases, such as tonsillitis and pharyngitis. It can also be seen in infectious diseases such as bacterial endocarditis and tuberculosis. To diagnose rheumatoid arthritis, it is necessary to check the anti-O and other indicators and combine with clinical manifestations. If the anti-O+RF are high, it means that rheumatoid arthritis is very likely, and it is recommended to do further examination to clarify the diagnosis and timely treatment. The patient should pay attention to eating hot food and keeping the joints warm. Patients are advised to go to the hospital for examination and consult a professional doctor to avoid delaying their condition.