A comparative study of different methods for measurement of rheumatoid factor in dog serum.

An enzyme linked immunosorbent assay (ELISA) technique was developed and compared with two routinely used methods, latex agglutination and Rose-Waaler hemagglutination, for the measurement of Rheumatoid Factor (RF) in dog serum. The frequency of positive samples for IgM-RF was rather low, about 8-12% of the 460 dogs with different rheumatic disorders being classified as positive by these methods. It was further concluded that the latex agglutination test used in this study (Synbiotics CRF Kit) should be performed only on heat inactivated serum (56 degrees C for 30 minutes) thereby significantly reducing the frequency of weak, probably false, positive agglutination reactions. When this was considered, a significant correlation was obtained for the three different techniques for RF estimation in serum from normal control as well as rheumatic diseased dogs.