[Immunologic diagnosis of rheumatoid polyarthritis using a new micromethod of quantitative hemagglutination of the rheumatoid factor: the polyartiter].

A new micromethod of quantitative haemagglutination of the rheumatoid factor (class IgM) "polyartitre" was studied and compared with the classical Waaler-Rose reaction to the polyartest and to the rheumalatex using sera from 40 patients with rheumatoid arthritis, confirmed both radiologically and clinically. Thirty controls were selected from among the blood donors and 29 subjects with viral infections, hepatic or systematic illnesses or metabolic troubles. This method presents an excellent concordance with other methods. It is quantitatively more sensitive as the rheumatoid factor titres are higher than those obtained with the classical Waaler-Rose reaction. The polyartitre is simple to perform, easy to read, specific and reproducible, and the results are expressed in international units.