There is no single test that conclusively diagnoses RA, but rather several factors are used.
anti-cyclic citrullinated peptide (Anti-CCP), and antinuclear antibody (ANA) are among the lab tests used.
Imaging tests include X-rays, MRIs, ultrasounds, and CT scans.
Verywell / Joshua Seong
This article discusses rheumatoid arthritis tests.
It explains the common lab tests and imaging studies used to make an RA diagnosis.
It also covers tests used to monitor disease progression and how your medication is working.
Get our printable guide for your next healthcare provider’s appointment to help you ask the right questions.
Verywell / Joshua Seong
What Is Rheumatoid Arthritis?
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.
© Verywell, 2018
The exactcause of RAis 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.
Blood Tests to Diagnose Rheumatoid Arthritis
There is no one specific test that conclusively diagnoses RA.
It is possible to measure RF with a blood test.
In addition, some people have a positive RF blood test because of other conditions and not RA.
You do not need to make any special preparations before the blood test.
A laboratory will test your blood to check for the presence of rheumatoid factor.
The blood test is a low-risk procedure that should not have any serious side effects.
A positive RF blood test means that you have rheumatoid factor in your body.
This indicates that you may have RA or another autoimmune condition.
A positive RF blood test is not a definitive diagnosis for RA.
A negative RF blood test does not automatically mean you do not have RA.
Some people with RA have negative RF blood tests.
Your healthcare provider will order more tests before diagnosing RA.
Its other names include citrulline antibody, cyclic citrullinated peptide antibody, anticitrullinated peptide antibody, and ACPA.
It is rare for a person without RA to have anti-CCP.
If you test positive for both antibodies, there is a strong chance you have RA.
A healthcare professional will collect your blood from your vein during an anti-CCP blood test.
The blood sample will go to a laboratory, which will check for the presence of anti-cyclic citrullinated peptide.
The anti-CCP blood test is a low-risk procedure that does not have any side effects.
A positive anti-cyclic citrullinated peptide blood test means you have these antibodies in your blood and may have RA.
A negative anti-CCP blood test means you do not have the antibodies, but you may still have RA.
A positive anti-CCP and positive RF blood test indicate there is a strong chance you have RA.
Get our printable guide for your next healthcare provider’s appointment to help you ask the right questions.
Erythrocyte Sedimentation Rate (ESR)
Erythrocytes are red blood cells.
If the red blood cells settle quickly, then you may have inflammation in your body.
Inflammation can make erythrocytes clump together, which makes it easier for them to settle in a test tube.
Other names for this test include SED rate and Westergren sedimentation rate.
You do not need to do anything special to prepare for the blood test.
A laboratory will measure the erythrocyte sedimentation rate.
An ESR test cannot diagnose a specific disease.
It can only show if there is inflammation in your body.
A moderately increased ESR can be observed with anemia, infection, menstruation, or pregnancy.
A normal ESR helps exclude inflammation, particularly chronic inflammation.
The ESR test is rarely done on its own to diagnose RA.
C-Reactive Protein (CRP)
Your liver makes C-reactive protein (CRP).
The levels of CRP increase when there is inflammation in your body.
It is possible to measure CRP levels with a blood test.
Similar to the ESR test, CRP cannot definitively diagnose RA or another autoimmune condition.
During the CRP test, your blood will be collected from a vein, so it can be analyzed.
You do not need any special preparations before the test.
It is a low-risk procedure without side effects.
A high C-reactive protein blood test shows that you have inflammation in the body.
A low CRP blood means it is less likely there is inflammation in the body.
Even if you have a high CRP test result, this does not automatically mean you have RA.
You may have an infection or another inflammatory disease.
Being overweight, smoking, and not exercising can also lead to high C-reactive protein levels.
Your healthcare provider will order more tests if the results are positive.
It is called antinuclear because it attacks the nucleus (center) of a cell.
Antinuclear antibodies can damage healthy tissues and cells in the body.
An ANA test measures the antinuclear antibodies in your blood to determine if you have an autoimmune disorder.
The antinuclear antibody blood test cannot show if you have a specific disease, like RA.
It is a step toward diagnosis.
You do not need to prepare for an ANA test.
A positive ANA test means you have antinuclear antibodies in your body.
A negative ANA test indicates that you do not have these antibodies.
A positive test is not a definitive diagnosis of RA.
You may have another autoimmune condition or an infection that causes the positive results.
Your healthcare provider will order other tests before diagnosing RA.
A CBC test can measure:
Blood will be collected from your vein during a CBC test.
The sample will go to a laboratory for testing.
A CBC test does not give a definitive diagnosis for RA.
Low white blood cell counts can indicate an autoimmune condition, cancer, or bone marrow problems.
High white blood cell counts can mean you have an infection or inflammation.
Your healthcare provider will request other tests.
This will include blood, urine, and imaging tests.
Lab tests used for both diagnosis and monitoring of RA include ESR, CRP, and CBC.
RA disease activity is also monitored with a blood test called multi-biomarker disease activity (MBDA).
Your healthcare provider may monitor you more closely for infections as well.
There is no single blood test that can provide a definitive diagnosis for RA.
Thus, your healthcare provider will order multiple tests and also check your symptoms and medical history.
Verywell, 2018
Arthritis Foundation.Rheumatoid Arthritis: Causes, Symptoms, Treatments and More.
Centers for Disease Control and Prevention.Rheumatoid arthritis (RA).
Rheumatoid Arthritis Support data pipe.RF test: What is the normal range for a rheumatoid factor test?
U.S. National Library of Medicine: MedlinePlus.Rheumatoid factor (RF) test.
U.S. National Library of Medicine: MedlinePlus.CCP antibody test.
U.S. National Library of Medicine: MedlinePlus.Erythrocyte sedimentation rate (ESR).
U.S. National Library of Medicine: MedlinePlus.C-reactive protein (CRP) test.
U.S. National Library of Medicine: MedlinePlus.ANA (antinuclear antibody) test.
U.S. National Library of Medicine: MedlinePlus.Complete blood count (CBC).
National Institute of Arthritis and Musculoskeletal and Skin Diseases.Diagnosis of rheumatoid arthritis.
Arthritis Foundation.Testing for rheumatoid arthritis.
