The Latex-Fixation Reaction in Nonrheumatic Diseases

THE serum agglutinating factor for amboceptor-sensitized or FII (fraction II)-coated erythrocytes and latex particles is still thought to be specific for rheumatoid arthritis and closely allied diseases,1 , 2 and the variable occurrence of positive reactions in control subjects has not been satisfactorily explained. The incidence of these so-called "false-positive" reactions in serums from normal subjects and patients with nonrheumatic diseases varies in different reports from less than 1 per cent to as high as 30 per cent and is not related to the agglutinating system used; claims for both increased sensitivity in, and specificity for, rheumatoid arthritis by any particular system . . .