Evaluation of rheumatoid factor tests

Fourteen (4 per cent) of 340 blood donors showed the presence of rheumatoid factor and some of these were studied in detail. One young donor with very high titers of rheumatoid factor and a 22S component, followed for over two years, has shown no clinical evidence of disease. The sensitized human cell test compares favorably with latex reagent. Both methods are more sensitive and less specific than the sensitized sheep cell test.