Patients who received false negative test results waited over six weeks longer for referral to an arthritis specialist, the study found.
Most RF tests take place in primary care and are used in referral decisions. However, RF antibodies are only detected in around eight out of 10 patients with arthritis and do not always show up in the early stages of the condition.
Dr Chris Deighton, president of the British Society for Rheumatology, said GPs should ‘realise that the diagnosis of early inflammatory arthritis is largely a clinical one, relying on symptoms and signs of inflammation, rather than tests which may be misleading’.
He added that it was important to raise the profile of early symptoms of inflammation so that patients do not delay visiting their GP.
Researchers from the Universities of Oxford and Bath looked at data from the GP records of 64,000 patients given the RF test between 2000 and 2008.
Among the 1,800 diagnosed with rheumatoid arthritis within two years, 800 had initially showed a negative result on the RF test. These patients were not referred as promptly as those with a positive test result and waited an extra 45 days on average before referral.
The study will be presented at the Rheumatology 2014 conference next month.