How is early rheumatoid arthritis diagnosed?

If you go to a doctor with signs of rheumatoid arthritis, the following diagnostic tools can be used first to try to find out for sure:

• Blood test for antibodies: Specific kinds of antibodies in your blood can be a sign of rheumatoid arthritis. These include antibodies called rheumatoid factors and “antibodies to citrullinated protein antigens” (ACPA).
• Blood test for signs of acute inflammatory reactions: One thing that can be looked for is C-reactive proteins (CRPs). If there is an inflammation in the body, more of these proteins are released. The erythrocyte sedimentation rate (ESR) can reflect the degree of inflammation in the body too. This is a measure of how long it takes for red blood cells to settle at the bottom of a test tube. Faster-sinking red blood cells are a sign of inflammation.

If these tests suggest that it is likely to be rheumatoid arthritis, further examinations (including imaging techniques) can be used. These include:

• Ultrasound: Ultrasound scans can help doctors to see early signs such as inflammations and a build-up of fluid, as well as an increased blood supply to the mucous membranes in the joint.
• X-rays: X-ray images can show whether the bone or cartilage of the joint has already been damaged.
• Magnetic resonance imaging (MRI): MRI images allow doctors to get a very clear picture of bones, joints, tendons and muscles. But they often find abnormalities that don't have anything to do with rheumatoid arthritis.

Inflamed joints or abnormal blood test results alone do not allow for a reliable diagnosis of early rheumatoid arthritis. They might be caused by something else instead. The more signs of rheumatoid arthritis someone has, the more likely they are to actually have the disease.