Diagnostic Performance of Anti-RA33 Antibodies in Comparison with Rheumatoid Factor (RF) Positive and Negative Patients in Coimbatore Districts of Tamil Nadu.

Abstract

Rheumatoid factor (RF), an immunological marker is the very first sero-marker used in the diagnosis of RA. An alternative to this scenario was seemed to have been aided by another marker, RA33 in identification of RA patients, who come under the category of sero-negativity RF tests. The main aim is to compare Rheumatoid Factor (RF) and Anti- RA33, to ensure which marker is more effective in diagnosing the rheumatoid arthritis patients. The cross sectional study was conducted for about three years from February 2020 – March 2023. A total of one hundred and fifty serum samples were collected from patients which includes 70 seropositive for RA and remaining 80 from seronegative RA patients. Among the 70 RA positive patients, 19 positive for anti-RA33 antibodies and the remaining 51 were negative. In case of 80 RA negative patients, 16 were positive and remaining 64 negative for the same. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 54.29%, 55.65%, 27.14% and 80.0% respectively. Anti RA33 has proved to be an amazing biomarker for seropositive as well as seronegative patients. In the case of seronegative patients, where RF is negative or undetectable, Anti RA33 serves as an indeed essential marker. The study concludes that anti-RA33 antibodies could be a good marker but statistically couldn’t be able to make a decision that it is a better marker than the RF