How Do You Test for Rheumatoid Arthritis? Here’s How It Is Diagnosed

Rheumatoid arthritis (RA) is a type of arthritis. It causes painful swelling in the joints, especially in the hands and feet. RA is an autoimmune condition. When you have RA, your immune system causes too much inflammation in the body, and it impacts your joints. This sets it apart from more common types of arthritis like osteoarthritis, which is due to the wear and tear of aging.

Diagnosing RA can be hard since there’s no single test to diagnose it. In fact, if the symptoms and physical exam fit, RA can be diagnosed without any tests at all. 

How is RA diagnosed?

To diagnose RA, healthcare professionals use clues from your symptoms and physical exam. Blood tests and imaging can provide additional information. But your symptoms and physical exam are the most important part of making the diagnosis. 

But diagnosing RA is quite complex. For example, it’s possible to have RA when specific testing is normal (more on this below). And it’s possible to not have RA, even when further testing is abnormal. If this sounds confusing, that’s because it is. But rheumatologists (RA specialists) are trained to sort this all out.

What are the symptoms and physical exam findings of rheumatoid arthritis?

Common signs and symptoms of RA include:

• Joint pain

• Swollen joints

• Joint stiffness (for 30 minutes or more a day)

• Fatigue

RA can affect almost any joint in the body, but it’s most common in the hands and feet. Symptoms must be present for at least 6 weeks before RA can be considered.   

Of note, RA does not cause back pain. RA typically only affects the spine in one joint, at the top of your spine near your skull. When this joint is affected by RA, it may cause a headache near the back and/or bottom of your head, but not back pain. 

What tests can help diagnose rheumatoid arthritis?

The following tests can be helpful when trying to diagnose RA. But it’s important to remember that none of these tests confirm RA, or rule it out completely. Symptoms and your physical exam findings are what matter most.

Blood tests 

Two tests may help diagnose RA if the symptoms and physical exam also fit:

• Rheumatoid factor (RF) 

• Anti-cyclic citrullinated peptide (anti-CCP) 

Some people with RA have both positive RF and anti-CCP tests. A positive test means these substances are present in your blood. Some only have one positive test. And, 1 in 4 people with RA don’t have any positive tests at all. When both blood tests are negative, it’s called seronegative rheumatoid arthritis. It’s called this because “sero” means blood, so “seronegative” means a negative blood test.

Some people with positive blood tests don’t have RA, and this is known as a false positive. False positives happen for other reasons. For example, chronic hepatitis C is one of many conditions that can also cause a positive RF. This highlights why positive testing alone does not diagnose RA. You must have matching symptoms. 

A positive anti-CCP test is associated with an increased risk of developing RA. Again, a positive test doesn’t mean that you have RA. But if you do develop symptoms later on, it’s important to connect with your healthcare team.

X-rays and imaging tests

If the diagnosis is unclear, X-rays and other types of imaging may help provide clues about RA: 

• X-rays: RA may damage joints in as little as 1 year if left untreated, and X-rays can show these joint changes. RA affects your joints in a unique way, so X-ray imaging can help with diagnosis.

• MRI: For a more detailed view of your joints, MRI may be a better option for some people. This can help people who have RA symptoms, but no signs on a physical exam like swelling. But if your joints are clearly swollen on an exam, this test is not needed.

• Ultrasound: This quick imaging test can detect inflammation in the joints. Ultrasounds are also helpful for those with symptoms of RA, but a normal physical exam. These tests can sometimes be performed during your physical exam. And ultrasound is cheaper and less time-consuming than MRI.

Who should be tested for rheumatoid arthritis?

If you have had symptoms of RA for more than 6 weeks, let your primary care provider know. They will likely order blood tests and imaging to get things moving. But more importantly, they can refer you to a rheumatologist to confirm your diagnosis. 

Remember, negative tests don’t rule out RA. If tests are negative, but your symptoms and physical exam fit, you may have seronegative RA. This is why seeing a rheumatologist is so important. 

RA is most common in your 50s and 60s, but it can affect anyone, at any age — even kids. There are some factors that may increase your risk of developing RA. These include:

• Having a first-degree relative with RA

• Smoking

• Female sex

What to expect if you are diagnosed with rheumatoid arthritis

A diagnosis of RA may feel overwhelming at first. But once the diagnosis is made, you and your rheumatologist can focus on getting you better. RA is a chronic condition — meaning there’s not a cure yet. But it’s very treatable. There are multiple treatment options, so feeling better is a very realistic goal. 

Treatment of RA involves immunosuppressants — medicines that decrease inflammation caused by the immune system. Common examples include:

• Methotrexate

• Humira

• Xeljanz

Rheumatologists are the experts when it comes to prescribing RA medications. But waitlists to see them can be long, and some people may not have access to one at all. If this is the case, don’t worry. Your primary care provider can also help you start treatment.

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Written by:

Samantha C. Shapiro, MD

Samantha Shapiro, MD, is a board-certified rheumatologist and internist with expertise in autoimmune and inflammatory conditions. She founded the division of rheumatology at Dell Medical School at The University of Texas at Austin.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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