[Dot immunobinding assay for detection of three types of rheumatoid factor and its clinical significance].

We set up a dot immunobinding assay method for determination of IgM-, IgG- and IgA-rheumatoid factor (RF) and report here the results in 86 patients with rheumatoid arthritis (RA). It was found that the positive rates of IgM-, IgG- and IgA-RF were 59.7%, 54.7% and 17.4% respectively. The total positive rate was 72.8%. The positive rate using the Latex method was only 43.0%. Our results reveal that dot immunobinding assay for RF is more sensitive than the Latex method. Furthermore, there was a profound correlation of IgG-RF with active stage and the frequency of extra-artivular manifestations in RA patients.