Diagnosing Rheumatoid Arthritis

Understand what tests may be needed to properly diagnose this chronic inflammatory condition

The early detection of rheumatoid arthritis (RA) is important to change the course of the disease. Unfortunately, no single test can adequately diagnose the condition, so individuals who suspect they may have RA may need to undergo a series of screenings and exams. Be sure to share with your doctor all of your symptoms, even if they do not seem related to the disease, advises Arthritis Research UK.

Initial Evaluation

To better understand your symptoms, their frequency or longevity, and your overall physical and mental health, your primary care physician (PCP) is likely to ask certain questions, such as:

  • Describe your symptoms. When did they start? When are they most severe? Does exercise help? Are you feverish or more fatigued than usual? Do these symptoms affect your ability to engage in normal activities?
  • Does arthritis run in your family?
  • Describe your lifestyle. Do you exercise? What are your eating habits? Do you drink or smoke?
  • Have you been exposed to hazardous chemicals or other substances at work or at home?
  • Have you had or do you currently have any other health problems?

As part of the initial physical exam, the doctor will also likely examine each joint, looking for signs of tenderness, swelling, warmth, and painful or limited movement. The number and pattern of joints affected can be an indicator of RA as the condition tends to affect joints on both sides of the body. The physical exam may look to reveal other signs, such as rheumatoid nodules or low-grade fevers, according to the Arthritis Foundation.

Blood Tests

Since symptoms can sometimes be very mild, a standard diagnosis may sometimes be difficult to make (according to the American College of Rheumatology (ACR), some viral infections can cause symptoms that can be mistaken for RA). If your doctor suspects RA, he might administer blood tests to examine levels of inflammation, antibodies, and so forth more closely. These lab tests, combined with your medical history and physical, can help your doctor make a clearer diagnosis.

Blood tests aim to examine:

  • antibodies - antibodies are small proteins in the bloodstream that help fight against foreign substances called antigens, according to ACR. The rheumatoid factor (RF) is an antibody found in about 80% of people with RA during the course of their disease, according to the Arthritis Foundation. Another antibody, anti-cyclic citrullinated peptide (anti-CCP), also occurs primarily in patients with RA (about 60% to 70%); another strong sign of RA.
  • inflammation - Erythrocyte sedimentation rate (ESR, or “sed rate”) and C-reactive protein (CRP) levels are markers of inflammation. High levels of these, while not specific to RA, could be another sign of the disease, according to the Arthritis Foundation.
  • anemia – a low red blood cell count could be a sign of RA.

While blood tests are not 100% effective in diagnosing RA (certain antibodies like the rheumatoid factor, for example, are also seen in people without RA), they can provide further evidence for the condition if multiple signs are found.


An x-ray, ultrasound, or magnetic resonance imaging (MRI) scan may be done as well to look for joint damage, such as erosions (loss of bone within the joint) and narrowing of joint space, according to the Arthritis Foundation. If a loss or narrowing of bones is not found, it does not necessarily rule out RA, but might show that the disease is in its early stages.

X-rays may also be ordered later in diagnosis to determine how the disease is progressing. According to Arthritis Research UK, the changes in bone and joint structure often show up in x-rays of the feet before they appear in other joints, so this could be a target for the doctor, even when you are not having any problems in that area. Your doctor may also use imaging to see whether a change in medication may be necessary.

Overall, imaging and blood tests are beneficial for early detection and monitoring of rheumatoid arthritis. Read more on our treatment page.

-Additional reporting by Steven Aliano

Updated on: 12/21/20
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Treatment for Rheumatoid Arthritis