Haematological reassessment of rheumatoid arthritis using an automated method

Thirteen haematological parameters were measured in 44 patients with rheumatoid arthritis (RA) and 39 disease control patients with ankylosing spondylitis (AS). Using a 10 000 cells per sample automated differential counter the most frequent abnormalities found were monocytopenia, low numbers of large unstained cells, basophilia and increased numbers of cells with high peroxidase activity (HPX). The total white cell count, lymphocyte and monocyte counts, the HPX count, platelet distribution width and erythrocyte sedimentation rate were able to distinguish RA from AS at a statistically significant level. Discriminant function analysis showed that a maximum of 55% of RA patients could be correctly classified into disease state when combinations of six out of seven laboratory tests were used.