Rheumatoid Arthritis Testing
What Is Rheumatoid Arthritis?
Rheumatoid arthritis (RA) is a chronic form of arthritis that causes stiffness, pain, and loss of mobility in the joints. Unlike more common forms of arthritis caused by wear and tear on the joints over time, RA is a type of autoimmune disorder.
In RA, the immune system attacks otherwise healthy joint tissue, causing inflammation and degeneration of the joints. Over time, cartilage, bone, and ligaments of a person’s joint can wear away and can cause the joint to become bent, twisted, or scarred.
Rheumatoid arthritis usually occurs in a symmetrical way. For example, if one wrist is affected, the other wrist is likely affected as well. Although RA most often affects the wrists and fingers, it can also impact other joints, including the elbows, neck, shoulders, hips, knees, and feet. RA may also cause other health conditions of the blood vessels, heart, lungs, nerves, eyes, and skin.
Although the cause of rheumatoid arthritis is unknown, researchers believe that this condition may develop when a person with an increased risk for RA is exposed to factors in their environment that trigger inflammation. Increasing age, female sex, and genetics increase a person’s risk for RA, while environmental triggers that can lead to inflammation and RA include certain bacterial infections, cigarette smoking, and stress.
However, just because someone has risk factors and is exposed to environmental triggers does not mean that they will develop RA. Similarly, some people develop RA with no known risk factors or triggers.
The Role of Rheumatoid Arthritis Testing
Rheumatoid arthritis testing is used to diagnose RA, evaluate the severity of a patient’s disease, monitor treatment, and detect potential side effects of treatment drugs:
- Diagnosis: Diagnostic testing helps determine the cause of a patient’s symptoms. If a doctor is concerned that a patient’s symptoms may be related to rheumatoid arthritis, testing can assist in diagnosing RA and ruling out other health conditions.
- Evaluating severity: The results of several laboratory tests can inform doctors about the severity of a patient’s RA, the amount of joint damage, and the prognosis or expected course of the disease.
- Treatment monitoring: Monitoring patients diagnosed with RA involves regular medical care, including doctor’s visits, laboratory testing, and imaging tests. Combining these strategies can assist doctors in tracking the progression of RA and understanding if treatment is effective.
- Detecting side effects: Testing may also be used to detect side effects caused by treatment drugs, as well as other health conditions that are more common in patients with rheumatoid arthritis, including osteoporosis, heart disease, and diabetes.
Who should get testing?
Patients who experience inflammation, pain, or loss of mobility in joints should discuss testing for rheumatoid arthritis with their doctor, especially if symptoms occur in multiple joints or in matching joints on both sides of the body, such as both wrists. Other symptoms of rheumatoid arthritis include:
- Stiffness in the morning for 30 minutes or longer
- Occasional fever
- Loss of appetite
- Weight loss
- Dry eyes and mouth
- Firm lumps beneath the skin
These symptoms are often due to something other than RA when they last less than six weeks. The longer a patient experiences symptoms, the more likely the symptoms are to be due to RA.
Diagnosing rheumatoid arthritis in its early stages can be challenging, as patients may experience few symptoms, but early diagnosis is important because early treatment may prevent joints from worsening or at least slow the process. When symptoms are present, they often differ from person to person and mimic the symptoms of other diseases. Testing is an important part of the process of determining whether symptoms are due to RA or another condition.
After receiving a diagnosis of RA, it’s important for patients to continue rheumatoid arthritis testing. Testing can assist doctors in assessing the severity of RA, as well as monitoring the efficacy of treatment, tracking disease progression, and detecting potentially serious side effects of treatment drugs.
Because rheumatoid arthritis is a complex disease, it may be helpful for patients to work with a rheumatologist who specializes in diagnosing and treating diseases of the joints, muscles, and bones. A rheumatologist can help patients understand the process of diagnosing RA, as well as create a plan for follow-up care after a patient is diagnosed.
Getting test results
How and when a patient receives test results depends on the type of test ordered and where the test samples are analyzed. Patients with questions about rheumatoid arthritis testing, including when to expect test results, should contact their doctor for more information.
After a test is performed, a patient’s doctor may call with results or schedule a follow-up office visit. Test results may also be delivered through the mail or an online health portal.
Results for at-home blood tests may be available within a few business days after the sample is received by the laboratory. At-home testing results may be provided through a smartphone app, website, or over the phone.
Types of Rheumatoid Arthritis Tests
In order to diagnose rheumatoid arthritis, a doctor begins by discussing a patient’s symptoms, understanding their medical history, and conducting a physical examination.
Laboratory tests are performed to help diagnose rheumatoid arthritis, to distinguish it from other forms of arthritis and conditions with similar symptoms, and to evaluate the severity of the disease. Laboratory tests used to diagnose and evaluate rheumatoid arthritis, as well as to rule out other conditions, include:
|TESTS RELATED TO DIAGNOSING RHEUMATOID ARTHRITIS|
|Test Name||Test Sample||What It Measures|
|Rheumatoid Factor (RF)||Blood sample||An antibody that is present in certain autoimmune disorders|
|Cyclic Citrullinated Peptide (CCP) Antibody||Blood sample||Anti-CCP antibodies present in certain autoimmune disorders|
|Erythrocyte Sedimentation Rate (ESR)||Blood sample||How quickly red blood cells settle in a test tube, which can indicate inflammation in the body|
|C-Reactive Protein (CRP)||Blood sample||A protein related to inflammation in the body|
|Antinuclear Antibody (ANA)||Blood sample||Various substances and features of the blood|
|Complete Blood Count (CBC)||Blood sample||Physical, chemical, and microscopic aspects of synovial fluid|
|Synovial Fluid Analysis||Synovial (joint) fluid sample||Physical, chemical, and microscopic aspects of synovial fluid|
Laboratory tests used to monitor rheumatoid arthritis and detect treatment side effects include regular testing of c-reactive protein and erythrocyte sedimentation rate, as well as hemoglobin, albumin, and platelet count. Additional tests used to detect side effects of treatment depend on the type of treatment or medication a patient is receiving.
Imaging tests may also be ordered during diagnosis, as part of a pretreatment evaluation, and after a patient starts treatment for rheumatoid arthritis. Ultrasounds and magnetic resonance imaging (MRI) assist doctors in diagnosing rheumatoid arthritis in its early stages, evaluating the extent of joint damage, and assessing the severity of the disease. X-rays may be used to detect joint damage that develops in more advanced RA, as well as to monitor the progression of RA over time.
Genetic testing may be used in planning treatment for rheumatoid arthritis. In order to understand if a patient’s body is able to metabolize a type of medication called thiopurine prodrugs, doctors may test patients for variants in the thiopurine methyltransferase (TPMT) and nudix hydrolase 15 (NUDT15) genes. Testing for drug metabolism is important to determine a safe dosage of these medications.
Getting Tested for Rheumatoid Arthritis
Testing for rheumatoid arthritis is ordered by a doctor or specialist if indicated by a patient’s symptoms. Blood and urine samples used for testing can be obtained in a doctor’s office or other medical setting.
Synovial fluid is a liquid that is located in spaces between a person’s joints, helping to cushion ends of bones and reduce friction during movement. For a synovial fluid analysis, a sample of synovial fluid is obtained during a procedure called a joint aspiration or arthrocentesis. During a joint aspiration, a doctor uses a needle to withdraw a sample of synovial fluid from a joint.
At-home tests are available that analyze several substances related to rheumatoid arthritis. However, it’s important to understand that at-home testing is not a substitute for medical care from a doctor or specialist and cannot diagnose RA. Options for at-home testing include:
- At-home rheumatoid factor (RF) testing: At-home rheumatoid factor testing detects levels of rheumatoid factor in the blood. Testing kits allow patients to obtain a sample of blood using a finger stick. Once a sample of blood is collected in a test vial, it’s sent to a laboratory for analysis.
- At-home cyclic citrullinated peptide (CCP) antibody testing: At-home CCP antibody testing detects the presence of CCP autoantibodies in the blood. which are a type of antibody that mistakenly attacks a person’s healthy cells. Testing for CCP involves taking a sample of blood through a finger stick, collecting the blood in a test vial, and mailing the sample to a laboratory for testing.
- At-home hepatitis testing: At-home hepatitis testing can detect antibodies and/or antigens related to the viruses that cause hepatitis. Taking an at-home hepatitis test entails pricking a finger to obtain a blood sample, collecting the blood sample in a provided testing container, and sending the sample to a laboratory by mail.
Sources and Resources
The following resources provide in-depth information about rheumatoid arthritis, including risk factors, symptoms, and treatment:
- Arthritis Foundation: Rheumatoid Arthritis
- American College of Rheumatology: Rheumatoid Arthritis
- National Library of Medicine: Rheumatoid Arthritis
- National Institute of Arthritis and Musculoskeletal and Skin Diseases: Rheumatoid Arthritis
A.D.A.M. Medical Encyclopedia. Rheumatoid factor (RF). Updated April 8, 2019. Accessed May 10, 2021. https://medlineplus.gov/ency/article/003548.htm
A.D.A.M. Medical Encyclopedia. Cholesterol testing and results. Updated January 7, 2020. Accessed May 10, 2021. https://medlineplus.gov/ency/patientinstructions/000386.htm
American Academy of Family Physicians. Rheumatoid arthritis. Updated October 6, 2020. Accessed May 10, 2021. https://familydoctor.org/condition/rheumatoid-arthritis/
American College of Rheumatology. Rheumatoid arthritis. Updated March 2019. Accessed May 10, 2021. https://www.rheumatology.org/I-Am-A/Patient-Caregiver/Diseases-Conditions/Rheumatoid-Arthritis
Arthritis Foundation. Rheumatoid arthritis: Causes, symptoms, treatments and more. Date unknown. Accessed May 10, 2021. https://www.arthritis.org/diseases/rheumatoid-arthritis
ARUP Consult. Rheumatoid arthritis. Updated October 2020. Accessed May 10, 2021. https://arupconsult.com/content/rheumatoid-arthritis
Centers for Disease Control and Prevention. Rheumatoid arthritis (RA). Updated July 27, 2020. Accessed May 10, 2021. https://www.cdc.gov/arthritis/basics/rheumatoid-arthritis.html
Centers for Disease Control and Prevention. Testing for TB infection. Updated March 8, 2021. Accessed May 10, 2021. https://www.cdc.gov/tb/topic/testing/tbtesttypes.htm
Kontzias A. Rheumatoid arthritis (RA). Merck Manuals Consumer Edition. Updated May 2020. Accessed May 10, 2021. https://www.merckmanuals.com/home/bone,-joint,-and-muscle-disorders/joint-disorders/rheumatoid-arthritis-ra
Kontzias A. Rheumatoid arthritis (RA). Merck Manuals Professional Edition. Updated May 2020. Accessed May 10, 2021. https://www.merckmanuals.com/professional/musculoskeletal-and-connective-tissue-disorders/joint-disorders/rheumatoid-arthritis-ra
MedlinePlus: National Library of Medicine. Rheumatoid arthritis. Published September 1, 2013. Accessed May 10, 2021. https://medlineplus.gov/genetics/condition/rheumatoid-arthritis/
MedlinePlus: National Library of Medicine. Rheumatoid arthritis. Published May 2, 2018. Accessed May 10, 2021. https://medlineplus.gov/rheumatoidarthritis.html
MedlinePlus: National Library of Medicine. Erythrocyte sedimentation rate (ESR). Updated July 31, 2020. Accessed May 10, 2021. https://medlineplus.gov/lab-tests/erythrocyte-sedimentation-rate-esr/
MedlinePlus: National Library of Medicine. CCP antibody test. Updated July 30, 2020. Accessed May 10, 2021. https://medlineplus.gov/lab-tests/ccp-antibody-test/
MedlinePlus: National Library of Medicine. AST test. Updated July 30, 2020. Accessed May 10, 2021. https://medlineplus.gov/lab-tests/ast-test/
MedlinePlus: National Library of Medicine. Complete blood count (CBC). Updated July 31, 2020. Accessed May 10, 2021. https://medlineplus.gov/lab-tests/complete-blood-count-cbc/
MedlinePlus: National Library of Medicine. Hepatitis panel. Updated July 31, 2020. Accessed May 10, 2021. https://medlineplus.gov/lab-tests/hepatitis-panel/
MedlinePlus: National Library of Medicine. ANA (antinuclear antibody) test. Updated November 30, 2020. Accessed May 10, 2021. https://medlineplus.gov/lab-tests/ana-antinuclear-antibody-test/
MedlinePlus: National Library of Medicine. C-reactive protein (CRP) test. Updated December 3, 2020. Accessed May 10, 2021. https://medlineplus.gov/lab-tests/c-reactive-protein-crp-test/
MedlinePlus: National Library of Medicine. Rheumatoid factor (RF) test. Updated December 3, 2020. Accessed May 10, 2021. https://medlineplus.gov/lab-tests/rheumatoid-factor-rf-test/
MedlinePlus: National Library of Medicine. Creatinine test. Updated December 22, 2020. Accessed May 10, 2021. https://medlineplus.gov/lab-tests/creatinine-test/
MedlinePlus: National Library of Medicine. Synovial fluid analysis. Updated March 8, 2021. Accessed May 10, 2021. https://medlineplus.gov/lab-tests/synovial-fluid-analysis/
Moreland LW, Cannella A. General principles and overview of management of rheumatoid arthritis in adults. In: O’Dell J, ed. UpToDate. Updated October 13, 2020. Accessed May 10, 2021. https://www.uptodate.com/contents/general-principles-and-overview-of-management-of-rheumatoid-arthritis-in-adults
National Institute of Arthritis and Musculoskeletal and Skin Diseases. Rheumatoid arthritis. Updated September 2019. Accessed May 10, 2021. https://www.niams.nih.gov/health-topics/rheumatoid-arthritis
National Institutes of Health. Painful joints? Early treatment for rheumatoid arthritis is key. Published April 2017. Accessed May 10, 2021. https://newsinhealth.nih.gov/2017/04/painful-joints
Sholter DE, Russell AS. Synovial fluid analysis. In: Shmerling RH, Calderwood SB, eds. UpToDate. Updated January 28, 2021. Accessed May 10, 2021. https://www.uptodate.com/contents/synovial-fluid-analysis
Taylor PC, Deleuran B. Biologic markers in the diagnosis and assessment of rheumatoid arthritis. In: O’Dell J, ed. UpToDate. Updated December 23, 2020. Accessed May 10, 2021. https://www.uptodate.com/contents/biologic-markers-in-the-diagnosis-and-assessment-of-rheumatoid-arthritis
Venables PJW, Baker JF. Rheumatoid arthritis symptoms and diagnosis (beyond the basics). In: O’Dell J, ed. UpToDate. Updated December 23, 2020. Accessed May 10, 2021. https://www.uptodate.com/contents/rheumatoid-arthritis-symptoms-and-diagnosis-beyond-the-basics
Venables PJW, Baker JF. Diagnosis and differential diagnosis of rheumatoid arthritis. In: O’Dell J, ed. UpToDate. Updated March 15, 2021. Accessed May 10, 2021. https://www.uptodate.com/contents/diagnosis-and-differential-diagnosis-of-rheumatoid-arthritis