[Comparison of the immunoenzyme test (ELISA) with other methods in the detection of rheumatoid factor]. / Komparacija enzimskog imunoloskog testa (ELISA) sa drugim metodama u detekciji reumatoidnog faktora.

IgM rheumatoid factor was detected, beside ELISA test, by Waaler-Rose, Latex agglutination and indirect immunofluorescent test. 107 patients hospitalized in the Clinic for heart diseases and rheumatism, as well as 50 healthy subjects were examined. In the first group were 50 patients with RA, 30 patients with other rheumatic diseases and 27 with nonrheumatic diseases. According to our results there was no significant difference between sensitivity of ELISA test and other laboratory tests used. ELISA test was positive in 94% of cases of RA, 20% in other rheumatic diseases and only in one case (3,7%) of a nonrheumatic disease. Compared with the control group in which there was no specific reaction, Waaler-Rose and immunofluorescent testing showed a nonspecific reaction in 2% and Latex test in 4% of all cases. Although ELISA test was not significantly sensitive as compared with other laboratory methods, according to our results, it has high reproducibility, specificity and precision (it is measured in international units/mL serum), and it allows following of the concentration of rheumatoid factor. Besides, ELISA test can be done on 100 specimen of blood within 6 hours and the results are known the same day.