GPs are being warned that a testing technique for arthritis is not perfect as it fails to pick up all cases of the disease.
Experts have called on doctors not to rely on the rheumatoid factor (RF) test as patients who receive a false negative result ultimately wait longer to see a specialist.
Researchers from the Universities of Oxford and Bath assessed data from the GP records of 64,000 patients given the RF test between 2000 and 2008. From a total of 1,800 people who were diagnosed with rheumatoid arthritis within two years, 800 had initially been given a negative result in the RF test.
On average, the patients who initially received a negative test result waited an additional 45 days before referral compared to those who had a positive result from day one.
Arthritis patients are among those who can benefit from mobility assistance such as stairlifts in the home, so any time lost at the diagnosis stage could have a significant impact, not only on treatment plans but also quality of life.
The research is set to be presented at the Rheumatology 2014 conference in April.
Dr Chris Deighton, president of the British Society for Rheumatology, said GPs should be aware 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 said the importance of noticing early symptoms needs to be well publicised so that people visit their GPs without delay.
Elsewhere, it was recently announced that a new pill made from rose-hip extract can reduce the agony felt by osteoarthritis patients by 90%.
Results from human trials suggest that the supplement called Gopo, named after a key ingredient of the plant, could represent a breakthrough for the six million Britons whose lives are blighted by joint pain.
Pills containing the supplement that cost just 15p each have now been made available in the UK for the first time. Scientists say the results are proof that the herbal remedy contains special properties that can alleviate the condition, especially in the hand.
Clinical trials involving 30 participants found that the specially-cultivated compound reduced nagging pain in nine out of 10 patients, Danish researchers reported.