A rheumatoid factor of 30 U/ml is considered high, with normal values below 20 U/m. High rheumatoid factor may be caused by rheumatoid arthritis, dry syndrome, tuberculosis and other diseases. 1. Rheumatoid arthritis: Rheumatoid arthritis is caused by autoimmune, genetic, infection and other factors. When the rheumatoid factor is 30U/ml in blood test, the patient will have high fever, joint pain, fatigue and other symptoms. 2. Dry syndrome: dry syndrome is considered to be caused by infection, heredity and other factors. Patients with high rheumatoid factor after blood test, the main symptoms of patients are dry mouth, dry eyes, low fever and so on. 3. Tuberculosis: tuberculosis is caused by the infection of tuberculosis mycobacteria complex, and the patients will have the phenomenon of elevated rheumatoid factor. Rheumatoid factor 30U/ml will appear in the blood test of patients, and the patients may show low fever, night sweating (abnormal sweating after going to sleep, and sweating stops after waking up), fatigue and so on. Rheumatoid factor 30U/ml is higher than the normal value, the patient should consult a doctor in time to check the cause of the disease, under the guidance of the doctor treatment.