The Hemagglutination Test in Rheumatoid Arthritis I. Use of Red Cell Pattern as Endpoint in the Method §

This is a description in some detail of the sensitized sheep cell hemagglutination test for rheumatoid arthritis as it is currently carried out in this Clinic. Sustained interest in the pathogenesis, natural history, and treatment of rheumatoid arthritis leads us to direct a significant portion of the investigative studies toward improvements in the serological method with fairly exact definition of its diagnostic and prognostic value. A lengthy test and the vagaries of rheumatoid arthritis suggest that the description of the method and its evaluation be treated separately. The poorly defined clinical landmarks of rheumatoid arthritis do indicate the need for such a diagnostic test. It is when the limits of clinical discernment and serological accuracy are mutually established that both can be used to full advantage. This report is rather strictly confined to the actual procedure. Data at hand will supply the material for its clinical counterpart. Meanwhile, Table 1 and a recent publication2 tell something of the performance of the hemagglutination test in rheumatoid arthritis.