If you have rheumatoid arthritis (RA), you may have heard of something called rheumatoid factor (RF). Rheumatoid factor is a protein that might be found in the blood.¹ Doctors check for rheumatoid factor to help figure out if someone has an autoimmune disease, such as rheumatoid arthritis or Sjӧgren’s syndrome.² When rheumatoid factor is found, it can help doctors determine if you have RA.¹ Higher levels of RF may provide further information on the long-term outcomes of your condition, as well as be a signal for your doctor to consider treatment differently.^3-6

Some members of myRAteam have written about their rheumatoid factor test results. For example, a member asked, “Has the rheumatoid factor shown up in everyone’s blood testing?”

One member responded, “I have a high positive rheumatoid factor,” while a different member said, “The rheumatoid factor has not shown up in my blood work.”

Just because someone has a positive rheumatoid factor test, that doesn’t mean they have RA.² However, around 80 percent of people with RA will have a positive rheumatoid factor test.⁷ If you have RA, keep reading to learn more about rheumatoid factor and what it could mean for treating your RA.⁸

1. Rheumatoid Factor May Help Decide Which RA Treatment You Should Try

Health care providers look at many different factors of RA and health when they’re trying to figure out the best treatment plan for a person’s RA. This is because different components of the disease can help doctors predict how a certain treatment may work.^9,10

When doctors are trying to figure out how to treat your RA, they may look at several details:

	How active your RA is — Based on results of medical tests or by counting how many of your joints hurt or are swollen because of RA11
	How high rheumatoid factor is in your blood — Doctors will see how high your disease markers, such as RF levels, are2,8
	Whether you have bone erosion — Bone damage from RA11
	Which joints RA affects10
	How old you are10
	How healthy you are overall and what other conditions you might have in addition to RA10,12

Your rheumatology doctor will think about these and other details when deciding on the best treatment plan for your RA. Considering these different factors will help your doctor know which type of treatment might work the best for you and which may not work as well.

2. Rheumatoid Factor May Help Decide When You Should Start an RA Treatment

Your doctor will decide when you should start RA treatment by considering different details about your RA. If you have high disease activity and high rheumatoid factor in your body, your doctor might recommend a more advanced treatment or that you start treatment more quickly.¹²

Doctors may look for other clues to figure out who needs what type of RA treatment or if they should start treatment sooner.¹² They’ll see if you have:

• Extra-articular disease — This means your RA is affecting parts of your body aside from your joints. If you have extra-articular disease, it could mean your RA is more severe.^11,12
• Functional limitation — This means your RA keeps you from moving normally because your joints are swollen or painful.¹²
• Bone erosions — This means some of your bone has been damaged by RA.¹²

RA is a condition that can get worse as time goes on. It can harm your joints and change their shape, which can make it hard for you to move around. Beginning treatment early can help stop your symptoms from getting worse and make movement easier.¹⁰

3. Rheumatoid Factor May Help Predict How Well Your RA Treatment Will Work

The goals of treating RA are to help lower your pain and swelling and to stop the condition from getting worse. There are many treatment options for RA. When picking the best treatment for you, your doctor will think about your overall health and some specific factors about your RA, such as the severity, disease activity, and how long you’ve had symptoms or a diagnosis.^9,10

Some studies have found that the presence or absence of rheumatoid factor, among other information about a person’s RA, may play a role in achieving remission with RA.¹³ For example, a study called “Diagnosis and Management of Rheumatoid Arthritis” looked at different details that can help predict if a treatment will help lessen someone’s RA symptoms.¹⁴

The study found that treatment reduced symptoms for some people with RA, but this improvement was more likely for certain people. People who had reduced symptoms were male, were younger than 40 years old, didn’t smoke, had less severe disease, and did not have positive rheumatoid factor, among other info about their RA.¹⁴

Rheumatoid factor, especially in higher levels, can be a sign that your RA is more severe, and it may affect how different treatments work for you.^12,14

GL-DA-2400559 © UCB Biopharma SRL, 2024. All rights reserved.
Date of preparation: December 2024