A haemagglutination method for detection of rheumatoid factor using preserved erythrocytes covalently coated with human IgG.

The preparation and use of a new haemagglutination assay for rheumatoid factor using preserved erythrocytes covalently coated with human IgG is described. Test serum heat inactivation or adsorption with uncoated erythrocytes is not required. This human IgG-coated erythrocyte agglutination test (H/CEAT) appears stable and specific, is suitable for routine determinations of serum IgM-rheumatoid factor, is simple to perform and compares favourably in these properties with either the Rose-Waaler or latex agglutination assays for rheumatoid factor.