Is There A Blood Test For Rheumatoid Arthritis?

Rheumatoid arthritis (RA) is the most common inflammatory form of arthritis. It affects roughly 2 million Americans. It is a chronic, systemic, autoimmune disorder for which there is no known cure. However, there are very effective medicine regimens that can control the disease and get it into remission.

The major reason, RA is not put into remission more often is the lack of a precise diagnosis. While there are many criteria that can point towards the diagnosis, it is often difficult early on to make sure a given person has the disease.

Multiple criteria established by the American College of Rheumatology can suggest the probability of RA. These include:

• Morning stiffness lasting more than one hour
• Simultaneous arthritis affecting three or more joints
• Arthritis affecting the knuckles (metacarpophalangeal joints) and close in finger joints (proximal interphalangeal joints)
• Symmetric arthritis
• Rheumatoid nodules
• Positive test for rheumatoid factor in the blood
• X-ray changes.

These criteria were formulated in the late 1980's and things have changed quite a bit.

First, x-ray changes are late and these cannot and should not be used to establish an initial diagnosis. Both magnetic resonance imaging and ultrasound are much more sensitive.They are also more sensitive to subtle changes.

Secondly, the use of blood testing has also improved.

Rheumatoid factor is present in only about 80 percent of people with RA. It can also be present in people with other diseases such as bacterial endocarditis, syphilis, sarcoidosis, leprosy, and other chronic inflammatory conditions.

Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) can also be effective in roughly quantitating the amount of inflammation present.

British researchers presented new findings at the American College of Rheumatology meeting held in Boston in November 2007 that could greatly facilitate early detection.

Patients with suspected rheumatoid arthritis are often tested for anti-cyclic citrullinated (anti-CCP) antibodies as part of their initial evaluation by a rheumatologist but not by the primary care doctor who may first have detected the condition.

The scientists retrospectively tested for anti-CCP in the blood samples of 98 newly-diagnosed rheumatoid arthritis patients. The blood samples hadn't been checked for anti-CCP before the patients' first visit with a rheumatologist. The researchers compared the actual treatment strategies without the anti-CCP results to treatment strategies proposed by three rheumatologists and a registered nurse who reviewed the patients' records and were given the retrospective anti-CCP test results.

The study found that prior knowledge of the anti-CCP results would have increased by 50 percent (from 19 to 28) the number of patients started on disease-modifying antirheumatic drugs (DMARDs) at the first rheumatologist visit. Earlier detection of the antibodies would have also led to a more intensive treatment regimen from the outset for eight patients.

"Having the results of this relatively inexpensive test available at the time of their first assessment of patients with a possible early inflammatory polyarthritis (arthritis affecting many joints) would allow rheumatologists to make a faster diagnosis and shorten the delay before treatment starts," lead investigator David O'Reilly, of West Suffolk Hospital, said in a prepared statement.

So... as our ability to make the diagnosis earlier becomes better, the chance for getting RA into remission and possibly curing it increases.