Blood Tests For Rheumatoid Arthritis
There are several types of blood tests that help your healthcare provider or rheumatologist determine whether you have RA. These tests include:
- Rheumatoid factor test. The RF blood test checks for a protein called rheumatoid factor. High levels of rheumatoid factor are associated with autoimmune diseases, especially RA.
- Anticitrullinated peptide antibody test . This test looks for an antibody thats associated with RA. People who have this antibody usually have the disease. However, not everyone with RA tests positive for this antibody. The anti-CCP test is more specific for RA than the RF blood test, and often is positive before the RF test.
- Antinuclear antibody test. The antinuclear antibody panel tests your immune system to see if its producing antibodies to the nucleus of cells. Your body often makes ANA antibodies as a response to many different types of autoimmune conditions, including RA.
- Erythrocyte sedimentation rate. The ESR test helps determine the degree of inflammation in your body. The result tells your doctor whether inflammation is present. However, it doesnt indicate the cause or site of the inflammation.
- C-reactive protein test. A severe infection or significant inflammation anywhere in your body can trigger your liver to make C-reactive protein. High levels of this inflammatory marker are associated with RA.
Risk Factors For Rheumatoid Arthritis
RA is an autoimmune disease that is probably related to both genetic and environmental risk factors. In terms of genetic factors, the risk of RA developing in first-degree relatives of a person with RA is 1.5-fold higher than in the general population. Monozygotic twins have higher concordance for RA than do dizygotic twins . The overall heritability of RA has been estimated to be about 5060%. The most potent genetic association is with HLA-DR4 and a shared epitope on the DRB0401 and DRB0404 alleles. More recently, polymorphisms ofPTPN22,STAT4, andCTLA4, among others, have been associated with RA in genome-wide association studies.
Females are two to three times more likely than males to be affected by RA. The explanation for the greater prevalence of RA in females and the role of hormones remain uncertain. Interestingly, during pregnancy the majority of women with RA experience a remission, but a flare can develop within weeks after delivery.
In terms of environmental exposure, cigarette smoke has been identified as a risk factor for RA and has been associated with both ACPA positivity and more aggressive disease. Infectious agents have long been considered a potential initiating factor for RA. Both bacterial and viral agents have been studied for their links to RA. Their mechanisms of action may be related to molecular mimicry with activation of the innate immune system.
Roberta Gualtierotti, … Pier Luigi Meroni, in, 2014
Mechanism And Comparison With Other Studies
Development of rheumatoid arthritis is thought to be an inflammatory process from early arthritis through rheumatoid arthritis and possibly to severe extra-articular rheumatoid arthritis.10132223 Among patients with early arthritis, only 40% are seropositive for rheumatoid factor, whereas in the final stage of rheumatoid arthritis 80% of patients are seropositive.1023 A current debate is whether elevated levels of rheumatoid factor, elevated levels of anti-citrullinated protein antibody, variations in the PTPN22 gene, or some combination of these offer the best means of predicting short term risk of rheumatoid arthritis.892425262728293031 However, the debate does not include long term risk prediction, simply because good evidence is lacking. Our finding that elevated rheumatoid factor levels are associated with an increased long term risk of rheumatoid arthritis provides such data. Unfortunately we do not have information available for elevated anti-citrullinated protein antibody or genetic variations in PTPN22. Our data show that elevated levels of rheumatoid factor can be present many years before the clinical manifestation of arthritis, supported by a few earlier studies.323334
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Living With Rheumatoid Arthritis
Research shows that people who take part in their own care report less pain and make fewer doctor visits. They also enjoy a better quality of life.
Self-care can help you play a role in managing your RA and improving your health. You can:
- Learn about rheumatoid arthritis and its treatments.
- Use exercises and relaxation techniques to reduce your pain and help you stay active.
- Communicate well with your health care team so you can have more control over your disease.
- Reach out for support to help cope with the physical emotional, and mental effects of rheumatoid arthritis.
Participating in your care can help build confidence in your ability to perform day-to-day activities, allowing you to lead a full, active, and independent life.
Everything You Want To Know About Rheumatoid Arthritis
Rheumatoid arthritis is an autoimmune disease that can cause joint pain, inflammation, and damage throughout your body.
The joint damage that RA causes usually happens on both sides of the body.
So, if a joint is affected in one of your arms or legs, the same joint in the other arm or leg will probably be affected, too. This is one way that doctors distinguish RA from other forms of arthritis, such as osteoarthritis .
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What Are The Four Stages Of Rheumatoid Arthritis
- Stage 1: In early stage rheumatoid arthritis, the tissue around your joint is inflamed. You may have some pain and stiffness. If your provider ordered X-rays, they wouldnt see destructive changes in your bones.
- Stage 2: The inflammation has begun to damage the cartilage in your joints. You might notice stiffness and a decreased range of motion.
- Stage 3: The inflammation is so severe that it damages your bones. Youll have more pain, stiffness and even less range of motion than in stage 2, and you may start to see physical changes.
- Stage 4: In this stage, the inflammation stops but your joints keep getting worse. Youll have severe pain, swelling, stiffness and loss of mobility.
Health Effects Of High Rheumatoid Factor Levels
The section below details some potential effects of elevated rheumatoid factor levels, according to clinical research. However, high levels can be found in those that are otherwise healthy. A doctor will evaluate test results based on several other factors, including symptoms, other health conditions, and other test results.
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Implications For Clinicians And Future Work
Our finding of a particularly high absolute risk of developing rheumatoid arthritis in women with elevated rheumatoid factor who smoked is yet another reason to promote cessation of smoking among such women. In addition, our finding of high risks of developing rheumatoid arthritis based on elevated levels of rheumatoid factor alone suggests the need for early referral to a rheumatologist or to early arthritis clinics for examination on the basis of a positive rheumatoid factor testeven in the absence of the typical arthritic joint symptomsbecause of the better response to therapy the earlier it is initiated in rheumatoid arthritis.
The superior specificity of anti-citrullinated protein antibody tests has somewhat diminished interest in rheumatoid factor at time of diagnosis of rheumatoid arthritis, but not necessarily when it comes to prediction of long term risk. Future work should include a comparison of rheumatoid factor and anti-citrullinated protein antibody tests for the long term prediction of development of rheumatoid arthritis. Also, larger studies might be able to confirm or refute that elevated rheumatoid factor is associated with future risk for other autoimmune rheumatic diseases.
Genes That May Play A Role
Certain variants in other genes may also contribute, including:
- STAT4, a gene that plays an important role in the regulation and activation of the immune response
- TRAF1 and C5, two genes associated with chronic inflammation
- PTPN22, a gene associated with both the development and progression of rheumatoid arthritis
It is possible that a specific combination of gene variants and/or genetic mutations may be enough to trigger the disease. Even so, not all people with these gene variants develop rheumatoid arthritis, and not all people with rheumatoid arthritis have these gene variants.
That means it’s likely other factors can trigger the autoimmune response, especially a genetic predisposed to the disease. One theory is that certain bacteria or viruses may inadvertently “confuse” the immune system. Four infections suspected of triggering rheumatoid arthritis in some people are:
Scientists believe that there may be cross-reactivity between these antigens and certain normal cells of the body. If so, antibodies produced in response to EBV, for example, may see EBV and a normal cell as the same thing. Even if the EBV infection eventually resolves, the body will remain on “high alert,” ready to pounce on any cell it believes to be EBV.
Other factors may also cause the immune system to malfunction. Some of these factors may be modifiable, meaning we can change them, while others may not.
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Rheumatoid Factors: Clinical Applications
1Division of Rheumatology, Istituto Gaetano Pini, Department of Clinical Science & Community Health, University of Milan, 20122 Milan, Italy
2Internal Medicine Section, IRCCS, Ca Granda Policlinico, Department of Pathophysiology and Transplation, University of Milan, 20122 Milan, Italy
Rheumatoid factors are antibodies directed against the Fc region of immunoglobulin G. First detected in patients with rheumatoid arthritis 70 years ago, they can also be found in patients with other autoimmune and nonautoimmune conditions, as well as in healthy subjects. Rheumatoid factors form part of the workup for the differential diagnosis of arthropathies. In clinical practice, it is recommended to measure anti-cyclic citrullinated peptide antibodies and rheumatoid factors together because anti-cyclic citrullinated peptide antibodies alone are only moderately sensitive, and the combination of the two markers improves diagnostic accuracy, especially in the case of early rheumatoid arthritis. Furthermore, different rheumatoid factor isotypes alone or in combination can be helpful when managing rheumatoid arthritis patients, from the time of diagnosis until deciding on the choice of therapeutic strategy.
However, although they owe their name to their first detection in RA patients, RFs are found in patients with other autoimmune and nonautoimmune diseases, as well as-in healthy subjects.
2. Methods of Detection
3. Rheumatoid Factors in Nonrheumatic Conditions
What Does Abnormal Test Results Mean
An abnormal test result means that you have a positive report or an RF value which is higher than the normal range. A positive test report indicates that you might have rheumatoid arthritis disease or Sjögren disorder. However, it should be remembered that a positive test result does not always mean that you have rheumatoid arthritis disease. Your doctor will take into account several other factors and do several other tests before doing the prognosis. On the other hand, a negative RF report does not completely rule out the possibility of the disease. Your doctor may order other tests to get the correct diagnosis.High levels of RF can indicate several medical conditions like: Mixed connective tissue disease. Lung disease.
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Quick Answers For Clinicians
The symptoms for rheumatoid arthritis are often nonspecific. Therefore, multiple conditions must be considered in the differential diagnosis of RA. Some of these conditions are , gout, and systemic autoimmune rheumatic diseases such as systemic lupus erythematosus, mixed connective tissue disease, and Sjögren syndrome. Careful evaluation is necessary for proper diagnosis and medical management of these conditions.
Autoantibodies such as rheumatoid factor , anticitrullinated protein antibodies , and anticarbamylated protein antibodies are a distinctive feature of rheumatoid arthritis . Additionally, their presence often precedes the onset of disease symptoms, making them useful tests for RA diagnosis. Autoantibody testing may also be useful in predicting the severity of disease course. As such, autoantibody testing leads to more accurate diagnosis and prognosis and often contributes to better disease management.
Can The Rheumatoid Factor Test Be Done During Pregnancy
Pregnant women with rheumatoid arthritis can develop a lot of complications during pregnancy or after delivery. They can develop pain and stress on hips, joints, and back as the baby develops. A reduction in milk production can also occur after delivery. A rheumatoid factor test is necessary for RA positive patients to control the disease and to provide relief to the patient.
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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 Are The Risk Factors For Developing Rheumatoid Arthritis
There are several risk factors for developing rheumatoid arthritis. These include:
- Family history: Youre more likely to develop RA if you have a close relative who also has it.
- Sex: Women and people designated female at birth are two to three times more likely to develop rheumatoid arthritis.
- Smoking:Smoking increases a persons risk of rheumatoid arthritis and makes the disease worse.
- Obesity: Your chances of developing RA are higher if you have obesity.
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Whats The Age Of Onset For Rheumatoid Arthritis
RA usually starts to develop between the ages of 30 and 60. But anyone can develop rheumatoid arthritis. In children and young adults usually between the ages of 16 and 40 its called young-onset rheumatoid arthritis . In people who develop symptoms after they turn 60, its called later-onset rheumatoid arthritis .
What Is A Rheumatoid Factor
A rheumatoid factor is created when an IgM antibody binds to the Fc portion of an IgG antibody. In simple terms, this is a situation where an antibody attacks another antibody. When you have many antibodies doing this at once, they can form large IgM-IgG antibody complexes, which can stimulate the immune system to make some serious inflammation.
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How The Test Is Performed
Most of the time, blood is drawn from a vein located on the inside of the elbow or the back of the hand.
In infants or young children, a sharp tool called a lancet may be used to puncture the skin.
- The blood collects in a small glass tube called a pipette, or onto a slide or test strip.
- A bandage is put over the spot to stop any bleeding.
How Sensitive And Specific Is The Rheumatoid Factor Test
Sensitivity refers to the proportion of people with a disease who will have a positive test, while specificity is the opposite: the proportion of people without the disease who will have a negative result.
For rheumatoid arthritis, the RF test has a sensitivity of 69 percent, according to a study in the journal Annals of Internal Medicine. This means that 69 percent of people with RA will be positive for rheumatoid factor. The sensitivity of the rheumatoid factor blood test is 85 percent, which means that 85 percent of the general population can be expected to test negative, but 15 percent might test positive even without having RA.
The tests for anti-cyclic citrullinated peptide , another kind of antibody, are a more specific alternative to rheumatoid factor, says Stuart D. Kaplan, MD, chief of rheumatology at South Nassau Communities Hospital in Oceanside, New York.
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Smoking And Obesity Add To The Burden Of Inflammation
Rheumatoid arthritis is caused by your immune system attacking parts of your own body as if they were dangerous germs. Among other tissues, the immune system targets membranes surrounding your joints, which are called the synovium. That leads to inflammation that can damage and even destroy the joints’ bone and cartilage.
As in other autoimmune disorders, such as lupus and psoriasis, the underlying cause of rheumatoid arthritis is not well understood. What doctors do know is that certain factorsincluding smoking and obesitycan place you at higher risk of not only getting the disease, but having more severe symptoms.
How Is Rheumatoid Arthritis Diagnosed
Your healthcare provider may refer you to a physician who specializes in arthritis . Rheumatologists diagnose people with rheumatoid arthritis based on a combination of several factors. Theyll do a physical exam and ask you about your medical history and symptoms. Your rheumatologist will order blood tests and imaging tests.
The blood tests look for inflammation and blood proteins that are signs of rheumatoid arthritis. These may include:
- Erythrocyte sedimentation rate or sed rate confirms inflammation in your joints.
- C-reactive protein .
- About 80% of people with RA test positive for rheumatoid factor .
- About 60% to 70% of people living with rheumatoid arthritis have antibodies to cyclic citrullinated peptides .
Your rheumatologist may order imaging tests to look for signs that your joints are wearing away. Rheumatoid arthritis can cause the ends of the bones within your joints to wear down. The imaging tests may include:
In some cases, your provider may watch how you do over time before making a definitive diagnosis of rheumatoid arthritis.
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