Sample: Fresh serum
Range: R.A., IU/mL Up 25 Negative 25 - 50 Weak 50 - 100 Increased > 100 Strong
Remarks: RA Test (RF Rheumatoid factor) is used in the differential diagnosis of rheumatoid arthritis and related diseases. About 80% of patients with clinically suspected rheumatoid arthritis have positive RA test, whereas seropositive cases are more serious than seronegative ones. Some rheumatoid arthritis patients with negative RA test will be positive for Anti CCP test. RA test may be positive in other than rheumatoid arthritis cases: patients with SLE, hepatitis, syphilis, cirrhosis of the liver.