تعيين فاكتور روماتوئيد به روش ELISA و لاتكس: يك مطالعه مقطعي

Evaluation of Rheumatoid Factor using ELISA versus Latex method: a cross sectional study

Background: Rheumatoid factor (RF ) is an IgM antibody against the Fe portion of IgG, which tog eth er form an immune complex . RF is an important criterion in the diagnosis of early-stage rheumatoid arthritis (RA) and prognosi s of RA path ogenesi s, as higher levels of RF indicate a higher pos sibility of more damage. Although 2/3 to 3/4 of pati ents that undergo ordinary standard tests and have final clini cal diagnosis are also positive for RF, a 70-90% prevalence of RF among RA patients can be achieved, depending on the method of detection and the target antibody, IgG or IgM. In this study, we measured the frequency of IgG and IgM RF isotypes using the ELISA and latex agglutination methods and compare these result s with those of a hosp ital control gro up, tested using standard metbods, in order to determine the best method for the mea surement of RF . Methods: Of the patients referred to the Rh eumatology Clinic of Imam Khorneini Hospital during 2005-2006, one hundred randomly selected rheumatoid arthriti s patients, 75 fem ale s and 25 males, with cla ssical or definite rheumatoid arthritis (defined by the criteria of the American College of Rheumatology), with a short disea se duration of 12-24 months, underwent testing for RF usin g the latex method for IgM and ELISA for IgM-IgG. The healthy control group (75 females and 25 male s) were tested for RF using the ELISA method for rgM-IgG. The variables were compared usin g the Pearson ʹs Chi-square test. Results: We found that the measurement of RF among RA pati ent s using did not differ significantly between the two methods. The inunune complex in RA is mainly IgM. The pos itive IgM results in RF patients using two similar meth ods showed a signi ficant relationship by Pearsonʹs corre la tion co-efficient (r=0.60, p