[Rheumatoid factor].

Abstract

To know the present situation of rheumatoid factor(RF) measurements, the questionnaire was sent to 82 University or College hospitals in Japan and regional 133 hospitals in Fukushima prefecture. Evaluation of qualitative RF kits commercially purchased in Japan was also performed. In RF measurement, quantitative methods have been increasingly used compared with semiquantitative or qualitative methods. Among quantitative RF measurement methods, latex immunoassay including latex-turbidimetry and latex-nephelometry is most frequently used. The reference values of RF distributed widely ranging from 5 to 40 unit. The 1997 JMA survey still showed interlaboratory differences in quantitative RF measurement. Qualitative RF kits were also shown to have variety of reactivities. To promote the improvement of current situation in RF measurement, "arbitrary" reference materials should be established urgently.