These recommendations are based on the National Institute for Health and Clinical Excellence (NICE) guideline Rheumatoid arthritis: national clinical guideline for management and treatment in adults [National Collaborating Centre for Chronic Conditions, 2009; NICE, 2009].

• The diagnosis of rheumatoid arthritis (RA) should be based on clinical findings. If RA is suspected, referral to a specialist is necessary to confirm the diagnosis as blood tests and radiography may be normal in the early stages of RA, particularly if synovitis is only affecting the small joints.
• A specialist will carry out tests to support or refute the diagnosis of RA, to gather information on prognosis, and to guide treatment. If investigations are started in primary care, the results will provide further information for the specialist, speeding up the diagnostic process.
• After reviewing good quality evidence (two meta-analyses, three case-controlled studies, and 12 case series), NICE concluded that rheumatoid factor, anti-cyclic citrullinated peptide (anti-CCP) antibodies, and erosions on hand radiographs are useful predictors for diagnosing RA. Elevated CRP is a poor predictor.
• At presentation, a positive rheumatoid factor test detects less than half the people who eventually develop RA.
• Inflammatory markers are no different in people presenting with inflammatory arthritis who eventually develop RA compared with those who do not.
• Testing for anti-CCP antibodies is only useful if the person is negative for rheumatoid factor. If both antibodies are positive, the person will have a poorer prognosis. However, there is no evidence that a person with a positive anti-CCP antibody should be treated any differently than a person who is positive for rheumatoid factor.
• After reviewing the evidence (one case series), NICE stated that ultrasound and magnetic resonance imaging (MRI) scans are superior to clinical examination in the detection of synovitis, and that they are more sensitive to the presence of erosions and other early inflammatory signs and damage than conventional radiography. However, the long-term significance of this, and their limited availability in primary care, currently limits their use in practice.
• After reviewing good quality evidence (33 case series), NICE concluded that the presence of rheumatoid factor, anti-CCP antibodies, rheumatoid nodules, elevated inflammatory markers, poor grip strength, and an increasing number of swollen joints, were useful indicators of a poor prognosis for RA.