Tests for rheumatoid arthritis | Arthritis Foundation

By Mary Anne Dunkin | June 12, 2022

Diagnosing rheumatoid arthritis (RA) can take time. Like other forms of arthritis, diagnosis is largely based on the results of a medical examination and your symptoms. These may include joint pain, tenderness, and swelling affecting the same joint or joints on both sides of the body (such as both wrists or both knees); fatigue and fever. Laboratory tests and imaging tests can help your doctor make the diagnosis.

Diagnostic laboratory tests

Evidence of RA can be seen in the blood, so blood tests play an important role in diagnosis. Below are some of the tests your doctor may order.

Erythrocyte sedimentation rate (ESR or erythrocyte sedimentation rate). ESR can measure how much inflammation there is in your body by measuring how quickly red blood cells (erythrocytes) separate from other cells in the blood and accumulate as sediment at the bottom of a test tube. Because inflammation can be caused by conditions other than RA, the results should be considered along with those of other tests when making a diagnosis of RA.
C-Reactive Protein (CRP). This measures levels of CRP, a protein produced by the liver that indicates inflammation. High levels of CRP are common in RA and other inflammatory forms of arthritis. Because a high CRP can be present in many diseases and conditions, a high CRP in itself does not mean that you have arthritis or identify what form it may take. The results should be interpreted in the context of your symptoms, as well as the results of other tests.
Rheumatoid factor (RF). Rheumatoid factor is a protein produced by the immune system that can attack healthy tissues. High levels of rheumatoid factor could help your doctor make a diagnosis of RA. However, RF levels can also be high in other autoimmune diseases, so an RF test alone cannot be used to diagnose RA.
Anti-CCP antibody test (ACCP or PCC). This test is for a type of autoantibody called cyclic citrullinated peptide (CCP) antibodies, which can be found in the blood of 60% to 80% of people with rheumatoid arthritis. The test is usually done in conjunction with an RF test.
Antinuclear antibody (ANA) test. Antinuclear antibodies (ANA) are a type of autoantibody, a protein that attacks the body’s own tissues. The presence of ANA may indicate an autoimmune condition, including RA.

Diagnostic Imaging Tests

Imaging tests, along with a physical examination and laboratory tests, can help identify RA. These imaging tests can be used to diagnose RA.

Radiography. X-rays can show bone damage, characteristic of RA, where they join together at the joints. They are a common tool in diagnosis; However, because the damage caused by inflammation develops over time and may not be visible by x-ray early on, it may not be useful in diagnosing early RA.
Magnetic resonance imaging (MRI). MRI is a procedure that uses radio waves and a powerful magnet connected to a computer to create 3D images of the body’s internal structures. MRI can show changes in cartilage and bone that are indicative of RA.
Ultrasound. Ultrasound or ultrasound uses sound waves to create images of structures inside the body. This can be used to see changes in bone and cartilage that suggest RA before changes appear on the x-ray. Other benefits of ultrasound include its relatively low cost and the fact that it does not expose the body to radiation, such as x-rays.
Computed tomography (CT). A CT scan is an imaging procedure that combines a series of x-ray images to create cross-sectional images of parts of the body. Studies show that CT scans can be effective in looking at early bone erosions that occur with RA.

Laboratory test monitoring

Some of the same laboratory and imaging tests used to diagnose RA are also used to monitor disease progression and response to treatment. Your doctor may order other tests to look for side effects of medications used to treat RA or effects of the disease itself. Your doctor may order some of these lab tests during your treatment.

Erythrocyte sedimentation rate (ESR or erythrocyte sedimentation rate). A reduced sedimentation rate is an indication that inflammation is being controlled.
C-Reactive Protein (CRP). As with sedimentation rate, lower CRP levels indicate that inflammation is being controlled.
The MBDA test (Vectra-DA). This blood test looks for 12 proteins, hormones and growth factors. It gives your doctor a unique disease activity score that can indicate how aggressive your disease is, how likely you are to have a flare when you stop taking medications, and what drug combinations may work best for you.
Complete blood count (CBC). While the CBC won’t necessarily tell your doctor how active your disease is, components of the test can help if you have complications from RA or its treatment. For example, low levels of red blood cells indicate anemia, which is common in people with RA. Sometimes, low levels of white blood cells, which are needed to fight infections, and low levels of platelets, which are needed to cause blood clotting, can occur in people taking biologics.
Liver enzyme (SGOT, SGPT, bilirubin, alkaline phosphatase). Measuring enzyme levels in your blood can help your doctor determine if you have liver damage, which may be related to RA treatment, an associated autoimmune condition, or RA itself.
Hematocrit (HCT) and hemoglobin (Hgb). These tests measure the quantity and quality of red blood cells. Lower red blood cell counts may mean that medications, such as NSAIDs or corticosteroids, are causing gastrointestinal bleeding.
Lipid panel. Because some RA medications, such as interleukin inhibitors and JAK inhibitors, can cause increases in triglyceride and cholesterol levels, your doctor may monitor those levels during RA treatment and prescribe medications to lower lipid levels if necessary.
Kidney function tests. Laboratory tests performed on blood and urine can tell your doctor how well your kidneys are removing waste products from the body. Kidney damage can occur from RA itself or from medications used to treat it, including nonsteroidal anti-inflammatory drugs (NSAIDs), disease-modifying antirheumatic drugs (DMARDs), corticosteroids, and biologics.

Listen Imaging tests

A variety of imaging tests can be used to monitor joint damage resulting from inflammation. They may be the same as those used to diagnose RA, including