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Rheumatology/connective tissue disease

The tests described in this section are very non-specific. Some (ANA, rheumatoid factor) are found in completely healthy people, particularly older women. These can also be transiently positive in infection or as the result of drugs (particularly anti DNA). This means that these tests should not be used as a 'screen' for investigating patients with raised ESRs or general malaise.

Rheumatoid factor is especially prone to misinterpretation. It is resent in 15% of normal individuals and is not diagnostic of rheumatoid arthritis. Rheumatoid arthritis is diagnosed by finding symmetrical peripheral polyarthritis with erosions on X-ray.

The half-life of IgG antibodies is about three weeks, so most forms of treatment will not produce rapid changes in autoantibody levels and repeat sampling more than every six weeks is probably unhelpful. We would advocate that it is nearly never useful to repeat positive ENA antibodies.

Patient information

Patient information is available from:


(Last updated March 25th 2014)