How is rheumatoid arthritis diagnosed?
No single test can give a definite diagnosis of rheumatoid arthritis in the early stages of the condition. Doctors have to arrive at a diagnosis based on your symptoms, a physical examination and the results of x-rays, scans and blood tests.
Because rheumatoid arthritis can affect other parts of your body besides your joints it’s important to tell your doctor about all the symptoms you’ve had even if they don’t seem to be related.
What tests are there for rheumatoid arthritis?
Blood tests for rheumatoid arthritis
Blood tests can measure inflammation. You may have one of these tests:
- erythrocyte sedimentation rate (ESR)
- C-reactive protein (CRP).
Both of these may show a high value when inflammation is present.
Blood tests can show if you’re anaemic and may be used to detect rheumatoid factor, which is an antibody produced by a reaction in your immune system.
About 4 out of 5 people with rheumatoid arthritis have positive tests for rheumatoid factor, but about 1 in 20 people without rheumatoid arthritis also have positive results. Only about half of all people with rheumatoid arthritis have a positive rheumatoid factor when the disease starts.
Another antibody test known as anti-CCP (anit-cyclic citrullinated peptide) is also available. People who test positive for anti-CCP are very likely to develop rheumatoid arthritis. And people who test positive for both rheumatoid factor and anti-CCP may be more likely to have severe rheumatoid arthritis.
X-rays and other tests for rheumatoid arthritis
X-rays will show any damage caused to your joints by the inflammation in rheumatoid arthritis. The changes often show up in x-rays of your feet before they appear in other joints, so your doctor may want to x-ray your feet even if they’re not causing you any problems.
Doctors are evaluating imaging techniques such as magnetic resonance imaging (MRI) scans and ultrasound scans to see how useful they are for early diagnosis and monitoring the condition’s progress. They may be more widely used in the future.
You may need repeat blood tests and x-rays from time to time to help your doctor assess how quickly your arthritis is developing and whether you need any changes to your medication.