Diagnosing RA

How is RA diagnosed?

Because RA is a complex disease with many possible causes, a definitive diagnosis may take time. You may not have all of the signs and symptoms of RA initially and they may develop over time. However, your doctor has a number of tools available to help him or her make a diagnosis, including:

Medical history

Understanding your medical history, including family history, may help your doctor diagnose your condition.

Joint exam

Your doctor will conduct a physical examination of your joints for swelling and tenderness, limited joint movement, and abnormal joint alignment. When you have RA, a physical exam of your joints may be regularly performed during your follow-up appointments.

Testimonial: Marie Barry, RA Patient Advocate

“The hardest part about this RA diagnosis was that there was no going back and it was my new normal.”

Laboratory tests

The following tests can be helpful in diagnosis:

  • Anti-cyclic citrullinated peptide (anti-CCP) is an autoantibody found in the blood and can be found before signs and symptoms of RA develop. Being positive for anti-CCP may indicate a higher risk of joint damage. Anti-CCP may be more specific for RA than RF (see below).
  • Rheumatoid factor (RF) is an autoantibody found in the blood and can also be found before signs and symptoms of RA develop; higher levels of RF may indicate a higher risk of joint damage. RF can be present in some patients without rheumatoid arthritis.
  • Erythrocyte sedimentation rate (ESR) measures inflammation.
  • C-reactive protein (CRP) measures a special type of protein that is produced in the liver during acute inflammation or infection.

A diagnosis of seropositive RA means that your RF or anti-CCP tests were positive. A diagnosis of seronegative RA means that both your RF and anti-CCP test were negative.

Imaging studies

Imaging technology may also be performed at the time of diagnosis of RA:

  • Radiographs are X-rays that help your doctor assess joint damage. Many patients already have joint damage by the time symptoms appear.
  • Magnetic resonance imaging (MRI) is an imaging technology useful for detecting inflammation in tissue cartilage and bone as well as bone erosions. Bone erosions can show up on an MRI up to a median of 2 years before they are visible on X-ray.
  • Ultrasound is an imaging technology useful for detecting inflammation and bone erosions. Like MRI, erosions may show up on ultrasound before they are visible on X-ray.