Updated 11 May 2016

Diagnosing rheumatoid arthritis

How is rheumatoid arthritis diagnosed?


A firm diagnosis of rheumatoid arthritis can be made when the patient fulfils four out of seven specified American College of Rheumatology (ACR) criteria.

However, the diagnosis may be tentatively made on the basis of clinical suspicion, even if these criteria are not present.

The diagnosis does not require use of blood tests or X-rays. It is a mistake to discount the diagnosis on the basis of normal investigations. The clinical examination is the most important aspect of assessment of the problem.

No specific tests

There are no specific tests for rheumatoid arthritis. A positive Rheumatoid Factor is found in less than 85% of patients with the disease. These patients are termed seropositive.

The test is negative in many patients, where it is termed seronegative. Although its presence does not establish the diagnosis, high levels of Rheumatoid Factor may predict a more severe and progressive disease, often with non-joint manifestations.

In addition, the test may be positive in other conditions and in the elderly. Once shown to be present, there is no value in repeated testing. A new antibody test, anti-CCP antibodies, has been shown to be more specific and useful in the diagnosis of early rheumatoid arthritis.

Those with active rheumatoid arthritis often have anaemia. The erythrocyte sedimentation rate (ESR) is increased in many patients with active disease, as is the C-reactive protein, (CRP). These markers of inflammation are useful when raised as they can be used to monitor progress.

Role of X-rays

X-rays are not always useful early in the disease, revealing mainly swelling of the soft tissues around the joint and fluid in the joint space.

However, the early appearance of erosion of bone around the joint margin indicates a more aggressive disease process and should prompt more aggressive treatment.

As the disease progresses, the abnormalities become more obvious, with narrowing of joint space and damage to joint margins. X-rays are useful in monitoring progress as they provide independent information as to the patient's response to particular therapy.

Read more:

Causes of rheumatoid arthritis

Rheumatoid arthritis drugs also help heart
Reviewed by Dr Dr I C Louw, Rheumatologist/Physician and Dr A Halland, Rheumatologist/Physician, March 2007


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Professor Asgar Ali Kalla completed his MBChB (Bachelor of Medicine and Bachelor of Surgery) degree in 1975 at the University of Cape Town and his FRCP in 2003 in London. Professor Ali Kalla is the Isaac Albow Chair of Rheumatology at the University of Cape Town and also the Head of Division of Rheumatology at Groote Schuur Hospital. He has participated in a number of clinical trials for rheumatology and is active in community outreach. Prof Ali Kalla is an expert in Arthritis for Health24.

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