A latex test for canine rheumatoid factor

Canine rheumatoid factor (RF) has been reported in several canine diseases, particularly in arthritis. Although RF can be assayed using IgG sensitized erythrocytes, the test has a number of disadvantages. As an alternative, latex sensitized with canine IgG was investigated as an assay of canine RF. The canine IgG-latex could be easily produced, was stable, and could be standardized with commercial antisera. The reagent detected RF of the IgM anti-canine-aggregated-IgG type. A comparison of the titres obtained using the canine IgG-latex reagent with those obtained using a rabbit IgG-erythrocyte reagent showed no correlation, suggesting that the two assays may detect RF of different specificities.