A Comparison of the Sheep Cell and Latex Agglutination Tests in Rheumatoid Arthritis.

The serum of patients with rheumatoid arthritis contains a factor which causes agglutination of sensitized particulate bodies. This phenomenon has been demonstrated using sheep red cells (Waaler, 1940), collodion particles (Wallis, 1946), bacteria (Wager, 1950), polysterene latex particles (Singer and Plotz, 1956), and bentonite (Bozicevich, Bunim, Freund, and Ward, 1958). Rose, Ragan, Pearce, and Lipman (1948) devised a diagnostic test using sensitized sheep red cells, since when a considerable literature has appeared describing modifications of this test, its clinical significance, and the mechanisms involved (Ziff, 1957; Kellgren and Ball, 1959). Because of its relative simplicity the latex test has recently attracted more attention and a number of modifications have been described, including the use of a glycine buffer in the place of the original borate buffer (Egghart, Wiedermann, and Braunsteiner, 1957; Valkenburg and Mos, 1958), a drop dilution technique (Rothermich and Philips, 1957), and the use of the patient's own gamma globulin (Singer and Plotz, 1958a). Bartfeld, Mahood, and Hartung (1958) and Burby and Behr (1958) have compared the results of sheep cell agglutination tests and the latex test. A slide agglutination test has recently been described (Singer and Plotz, 1958b). The object of the present investigation was to compare the results of sheep cell agglutination tests and latex tests performed in parallel on sera from a large physical medicine department, with the possibility of adopting the much quicker and simpler latex test in place of the sheep cell test.