Rheumatoid Factor And Anti
One blood test measures levels of rheumatoid factors in the blood. Rheumatoid factors are proteins that the immune system produces when it attacks health tissue.
About half of all people with rheumatoid arthritis have high levels of rheumatoid factors in their blood when the disease starts, but about 1 in 20 people without rheumatoid arthritis also test positive.
A related blood test known as anti-cyclic citrullinated peptide test is also available. Anti-CCPs are antibodies also produced by the immune system.
People who test positive for anti-CCP are very likely to develop rheumatoid arthritis, but not everybody with rheumatoid arthritis has this antibody.
Those who test positive for both rheumatoid factor and anti-CCP may be more likely to have severe rheumatoid arthritis requiring higher levels of treatment.
Seronegative Ra May Not Be The Correct Diagnosis
According to Cush and Domingues, a small percentage of people with the seronegative form of RA will do very well on therapy and go into remission, and others will experience severe disease and require medication. And still others will not respond to conventional treatment, which may be because they dont have RA at all. Spondyloarthritis conditions, which often affect the spine, are sometimes mistaken for seronegative rheumatoid arthritis.
Human Leukocyte Antigen Tissue Typing
This test checks for a genetic marker called human leukocyte antigen .
Some studies suggest that around 60% of RA cases may be inherited. If a person has specific antigens, it could mean that they have a higher likelihood of developing RA. However, other factors, such as tobacco use, can also trigger the condition.
HLA markers in the blood can help indicate the likelihood of developing an immune-related condition such as RA. These markers may also be a sign of another condition, such as ankylosing spondylitis or reactive arthritis.
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Seronegative Ra Could Become Seropositive Down The Road
Your rheumatoid arthritis markers may change over time from negative to positive, since many people with seronegative rheumatoid arthritis begin to develop RF or ACPA antibodies. It happens, but its not that common, says Dr. Domingues. Dr. Cush says people with seronegative rheumatoid arthritis may start to develop RF or ACPA within the first two years of diagnosis.
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Anticitrullinated Protein Antibody Test

An anti-CCP test, also known as ACPA, tests for an antibody associated with RA.
A research review from 2015 found that this test may identify people who are more likely to develop severe and irreversible damage due to RA.
If you test positive for anti-CCP antibodies, theres a good chance you have RA. A positive test also indicates that RA is likely to progress more rapidly.
People without RA almost never test positive for anti-CCP. However, people with RA may test negative for anti-CCP.
To confirm RA, your doctor will look at this test result in combination with other tests and clinical findings.
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Seronegative Ra Has Become More Common In Recent Years
According to CreakyJoints, a support, education, advocacy, and research organization for people living with arthritis and rheumatic disease, the majority of rheumatoid arthritis patients are seropositive. But while youre far less likely to be diagnosed with the seronegative type of the disease, those numbers are on the rise, according to a study published in the March 2020 issue of Annals of the Rheumatic Diseases. Between 1985 and 1994, only 12 out of 10,000 people with RA were seronegative. Between 2005 and 2014, that number crept up to 20 out of 10,000.
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The Role Of Blood Tests
Blood tests dont provide a simple yes-or-no answer to whether you have RA. But they can help your doctor steer toward a diagnosis. Blood tests narrow down options and suggest how your disease might progress.
After you receive a diagnosis of RA, continued blood tests will monitor the side effects of drugs used in treatment. They can also help track the progression of the disorder.
How To Test For Rheumatoid Factor
Testing for rheumatoid factor is done through a blood test. The blood is drawn then analyzed for the presence of this particular protein. If the results show a certain level of rheumatoid factor, then the test is said to be positive. Rheumatoid factor tests can also detect lower levels of rheumatoid factor, but the test result is not considered positive unless it crosses that threshold.
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Doctors Rely On Symptoms To Diagnose Seronegative Ra Not Just The Results From Blood Tests
Since blood work doesnt tell the whole story, your doctor will want to find out if youre experiencing these key symptoms:
- Inflammatory joint pain
- Morning stiffness for more than an hour in your hands, knees, elbows, hips, feet, or ankles
- Joint swelling, tenderness or pain, and sometimes redness. Typically, RA affects distal joints symmetrically
- Symptoms that appear symmetrically across the body and in multiple joints
- Fatigue
X-rays can also help your doctor make a diagnosis by showing signs of erosions or other changes in your bones.
What Causes Rheumatoid Factor
It is not exactly known what causes rheumatoid factor to develop in the blood. However, it is thought to be a combination of genetics and other external risk factors. The uncertainty may be because certain people have low levels of rheumatoid factor, which may not ever be enough to trigger a significant autoimmune response.
On the other hand, people who have high levels of rheumatoid factor may go on to develop autoimmune disorders like rheumatoid arthritis, while others with elevated rheumatoid factor may not develop an autoimmune disorder. It isnt completely known what triggers the autoimmune response that causes rheumatoid arthritis.
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Assessing Your Physical Ability
If you have been diagnosed with rheumatoid arthritis, your specialist will do an assessment to see how well you’re coping with everyday tasks.
You may be asked to fill in a questionnaire on how well you can do things like dress, walk and eat, and how good your grip strength is.
This assessment may be repeated after your treatment, to see if you have made any improvements.
Further information
The Diagnostic Criteria For Rheumatoid Arthritis

The diagnosis of rheumatoid arthritis cant be established with just one test. Instead, rheumatologists rely on a combination of your medical history, a physical exam, laboratory tests, and sometimes imaging tests to pinpoint the disease.
They also try to rule out the possibility of other conditions that may resemble RA, such as lupus, psoriatic arthritis, gout, or osteoarthritis. This is called a differential diagnosis.
To begin the diagnostic process, a rheumatologist will take your medical history, which includes asking questions about your current symptoms particularly pain, swelling, and stiffness and their location, duration, and severity.
Theyll also ask about your familys medical history as it pertains to RA and other autoimmune conditions. Conditions like RA can be more common in families with RA or other immune system-related health problems. For example, research recently published in the journal Arthritis Care & Research found that people who have a first-degree relative with RA are more than twice as likely as the general population to develop RA. A family history of lupus, scleroderma, thyroid disease, or inflammatory bowel disease also substantially increased the risk of RA.
Your rheumatologist will also perform a physical examination, testing each of your joints for things like swelling, tenderness, and limited range of motion. The location of affected joints is important to diagnosis.
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Blood Tests For Rheumatoid Arthritis
RA is an autoimmune disease. Several blood tests can detect immune system changes or antibodies that may attack the joints and other organs. Other tests are used to measure the presence and degree of inflammation.
For blood tests, your doctor will draw a small sample from a vein. The sample is then sent to a lab for testing. Theres no single test to confirm RA, so your doctor may order multiple tests.
Blood Tests To Help Diagnose Rheumatoid Arthritis
Watch:Rheumatoid Arthritis Overview Video
No single lab test can definitively diagnose the disease, but several lab tests can detect biological markers of RAmeasurable characteristics of the blood that are associated with rheumatoid arthritis.
The most useful biological markers for the diagnosis of RA are called rheumatoid factor and anti-CCP. Tests for these as well as several other biological markers are described below.
Rheumatoid factor. Rheumatoid factor is an antibody found in the blood. An elevated level of rheumatoid factor along with symmetrical joint pain is an indicator for rheumatoid arthritis.
While a helpful tool, this test alone cannot confirm or eliminate a diagnosis of rheumatoid arthritis. In fact, research shows:
- As few as 30% of people with early rheumatoid arthritis test positive for rheumatoid factor1
- About 80% of people with established rheumatoid arthritis test positive for rheumatoid factor1
- A small number of healthy people have elevated levels of rheumatoid factor
Elevated rheumatoid factor may also indicate another rheumatic disease, such as Sjögren syndrome, or other medical conditions, such as chronic lung disease and hepatitis C.
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How Rheumatoid Factor Affects Prognosis
Determining a prognosis for rheumatoid arthritis patients can be a complicated process. The disease affects different people in different ways. A prognosis can depend largely on the type and severity of symptoms the patient displays, as well as their medical history.
Many doctors and researchers feel that a positive rheumatoid factor test result may predict a more severe pattern of symptoms and overall disease course. Extra-articular symptoms like rheumatoid nodules may be more likely to form in patients who have positive rheumatoid factor blood test results. Other aggressive symptoms, though rare, could be more likely to occur in rheumatoid factor positive patients. These may include symptoms due to an autoimmune effect on the lung and heart.
Rheumatoid factor-positive patients may also have a higher disease activity score, meaning frequent flare-ups and fewer remission periods.
Keep in mind this isnt always the case. If rheumatoid factor is tested and symptoms are detected early, a diagnosis can be quickly reached. Early diagnosis means treatment can begin sooner, hence preventing further progression of joint damage, swelling and pain.
What Is Rheumatoid Arthritis
Similar to other autoimmune conditions, rheumatoid arthritis causes your immune system to attack the healthy tissues and cells in your body. Although RA usually damages the joints, it can affect other parts of the body, such as the eyes, heart, or lungs. RA can cause inflammation in joints located in the wrists, hands, knees, and ankles.
Symptoms can vary from person to person, but some early signs of RA include pain and tenderness in the joints. Over time, symptoms may get worse and progress to redness, stiffness, and swelling in the joints. Some people also have a low-grade fever and fatigue.
The exact cause of RA is not known, but several factors increase the risk of having this disease. It occurs more often in older adults and women. Smoking and being overweight also raise the risk of having RA. Certain genes have been linked to a higher chance of developing RA.
Illustration by Verywell
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Diagnosis And Management Of Rheumatoid Arthritis
AMY M. WASSERMAN, MD, Boston University School of Medicine, Boston, Massachusetts
Am Fam Physician. 2011 Dec 1 84:1245-1252.
Patient information: A handout on this topic is available at .
Rheumatoid arthritis is the most common inflammatory arthritis, with a lifetime prevalence of up to 1 percent worldwide.1 Onset can occur at any age, but peaks between 30 and 50 years.2 Disability is common and significant. In a large U.S. cohort, 35 percent of patients with RA had work disability after 10 years.3
SORT: KEY RECOMMENDATIONS FOR PRACTICE
Patients with inflammatory joint disease should be referred to a rheumatology subspecialist, especially if symptoms last more than six weeks.
Clinical recommendation | Evidence rating | References |
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In persons with RA, combination therapy with two or more disease-modifying antirheumatic drugs is more effective than monotherapy. However, more than one biologic agent should not be used at one time because of the high risk of adverse effects. |
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A guided exercise program can improve quality of life and muscle strength in patients with RA. |
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Cardiovascular disease is the main cause of mortality in persons with RA therefore, risk factors for coronary artery disease should be addressed in these patients. |
RA = rheumatoid arthritis.
SORT: KEY RECOMMENDATIONS FOR PRACTICE
RA = rheumatoid arthritis.
There Is No Way To Predict The Future Severity Of Seronegative Ra
Forecasting how any disease may progress is extremely difficult. Whether youre diagnosed with seronegative or seropositive, there are no set expectations of how either form of the disease will play out in an individual. Which type you have isnt all that important, since you treat them both the same way, says Domingues.
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The Erythrocyte Sedimentation Rate
The ESR measures the degree of inflammation in the joints. Blood is taken and placed in a small, thin tube, and the distance the red cells settle in one hour is measured. The more rapidly the red cells settle the more inflammation in the joints. One of the aims of treatment is to reduce the ESR to normal levels.
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Rheumatoid Arthritis Blood Tests

The rheumatoid arthritis blood tests that doctors perform to help diagnose the disease include:
- Rheumatoid factor
- C-Reactive Protein
- Antinuclear Antibody
None of these tests can singularly conclude that a patient has rheumatoid arthritis. Rather, doctors look at the combined results from all, alongside a number of other criteria including physical symptoms and genetics, in order to reach a rheumatoid arthritis diagnosis.
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What Do Rheumatoid Factor Test Results Mean
Testing positive for rheumatoid does not necessarily mean the patient has rheumatoid arthritis. A positive for rheumatoid factor test results means that it can lead to or is the cause of inflammatory symptoms from an autoimmune disorder.
In certain cases, however, patients may test positive for rheumatoid factor, yet remain healthy and never experience any obvious symptoms.
Rheumatoid factor can be present in patients several months or even years before clinical rheumatoid arthritis symptoms develop. Depending on the level of symptoms a patient exhibits, the rheumatoid factor test results can assist doctors in reaching a rheumatoid arthritis diagnosis.
Positive rheumatoid factor results in someone who has been clinically diagnosed with rheumatoid arthritis may also indicate the potential for a more aggressive disease course. This is possible in both children and adult patients.
Patients who test negative for rheumatoid factor but still exhibit symptoms and meet other diagnostic criteria may still be diagnosed with rheumatoid arthritis.
Seronegative Rheumatoid Arthritis Doesnt Need To Be Treated Differently From Seropositive
The treatment options available dont really differ regardless of what form of the disease you have. Whether you are diagnosed with negative or positive, be aggressive in treatment and stay ahead of the disease, advises Cush. The purpose of treatment in either case is to lessen pain and slow or prevent progression. Remission as early as possible is the goal, he says.
Standard drug therapy in early disease includes nonsteroidal anti-inflammatory drugs, such as ibuprofen or Celebrex to help relieve symptoms, and a class of drugs known as disease-modifying antirheumatic drugs that can help alter the course of the disease, says Domingues. DMARDs include methotrexate and hydroxychloroquine . More powerful drugs known as biologics can be prescribed for more severe cases.
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Tests That Help Diagnose Ra
To help confirm or disprove RA, your rheumatologist will also have lab tests done. The lab tests would point to likelihood of rheumatoid arthritis, as well as potentially rule out other possibilities on the differential diagnosis, says Dr. Neogi. These tests may include:
Erythrocyte sedimentation rate and C-reactive protein blood tests detect and measure inflammation in your body. If inflammation levels are elevated, it helps build the case for an RA diagnosis. If inflammation levels are normal, says Dr. Neogi, That might dissuade us from thinking about an inflammatory arthritis like rheumatoid arthritis, but would not rule it out. Since inflammation is present in many diseases, these tests do not confirm whether you have RA by themselves.
Rheumatoid factor and anti-cyclic citrullinated peptide antibody blood tests look for proteins associated with RA. Testing positive for one increases your chances of RA diagnosis, while testing positive for both raises your odds even more. However, up to 50 percent of RA patients dont have RF or anti-CCP antibodies. They are diagnosed based on other factors. In these cases, the RA is considered to be seronegative.
The possibility of some autoimmune disorders, such as lupus and Sjögrens syndrome, can be eliminated with the help of an antinuclear antibody blood test, while a synovial fluid analysis, which examines the fluid that lubricates your joints, can help count out gout by looking for crystals under the microscope.