Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

Rheumatoid factor (RF) is frequently tested in general practice where its utility as a diagnostic test for rheumatoid arthritis (RA) is not known. We undertook a retrospective cross-sectioal study to determine the utility and cost of RF in a primary care population. We compared RF with recorded clinical features based on the American College of Rheumatology (ACR) criteria as a diagnostic test for RA in 235 patients in general practice using receiver operating characteristic curves and calculated the cost of testing per case of RA. We analysed 36,191 RF requests made to one laboratory from 2003-2009 at a mean annual cost of £58,164 and the variation and annual cost of RF testing between 77 practices. The sensitivity and specificity of RF at the optimal cut-off value of 20 U/ml were 0.6 and 0.96 and that of two documented clinical ACR criteria were 0.9 and 0.92, respectively. No ACR criteria were documented in 150 (63.8 %) patients who had RF tested. The overall cost of RF testing per case of seropositive RA was £708.75. Of all RF requests, 66.6 % was made by GPs, 7.0 % by rheumatologists and 26.4 % by other hospital departments. The proportion of positive tests was 5.8 % in primary care and 17.7 % in rheumatology. The mean number of tests performed annually in primary care was 4.65 (SD 2.7) per 1,000 patients. RF is less sensitive for RA than clinical features in primary care and is frequently requested in cases without clinical evidence of the disease, adding to the overall cost. © 2013 Clinical Rheumatology.

Original publication




Journal article


Clinical Rheumatology

Publication Date





1089 - 1093