Types of rheumatoid arthritis
Rheumatologists divide rheumatoid arthritis into two main types: seropositive and seronegative rheumatoid. This classification is based on the seropositivity (presence of rheumatoid factor (RF) and cyclic citrullinated peptides) of the blood tests of rheumatoid patients. The purpose of this classification is to detect the response of rheumatoid patients to medication, but many doctors do not rely on this classification in choosing the course of treatment.
What are the differences between seropositive and seronegative rheumatoid arthritis?
1. seropositive rheumatoid arthritis (RA)
Seropositive patients are found to be about 60-70% of rheumatoid patients. Statistics show that rheumatoid patients who have tested positive for rheumatoid factor are more likely to experience extra-articular symptoms. Recent studies reported that seropositive patients would have tested positive RF if they were tested 5 to 10 years before the development of rheumatoid symptoms. Neither Seropositivity nor any blood test proves a bad prognosis. Seropositive rheumatoid is more easily diagnosed so it is managed earlier.
2. seronegative rheumatoid arthritis (RA)
Seronegative patients are estimated to be about 35 -40% of rheumatoid patients. Seronegative patients who test negative RF are harder to be diagnosed than seropositive patients. Rheumatoid factor (RF) is considered an important indication for RA. The absence of rheumatoid factor from patients’ blood may lead to a misdirected diagnosis. Doctors may mistake seronegative RA with osteoarthritis or gout. It is believed that seronegative rheumatoid arthritis has a mild course with fewer complications than seropositive rheumatoid. Extra-articular manifestations of seronegative patients are less reported by rheumatologists.