Rheumatoid arthritis (RA) is challenging to diagnose, especially in the early stage, because the signs and symptoms are similar to many other conditions. Healthcare providers rely on a physical exam, family medical history, several blood tests, and imaging such as X-rays, MRIs, and ultrasound. MRI and ultrasound images can reveal signs of RA at an early stage and guide your treatment by showing the extent of your joint damage.
Rheumatoid arthritis is an autoimmune disease. That means the immune system mistakenly attacks healthy tissues lining the joint, causing inflammation and pain. Getting an early and accurate RA diagnosis allows you to start the treatment you need to protect your joints and put the disease into remission.
Verywell
Physical Exam
The journey toward getting a rheumatoid arthritis diagnosis begins with a comprehensive physical exam, assessing your overall health, and paying special attention to your joints. Your healthcare provider will identify RA symptoms, such as swelling, stiffness, pain, limited movement, and joint deformities. They will also determine if your symptoms could be from other causes of joint pain like osteoarthritis.
| Rheumatoid Arthritis | Osteoarthritis | |
|---|---|---|
| Areas Affected | Tends to affect multiple joints (polyarthritis) | Usually affects the hands, feet, knees, and spine; sometimes involves just a single joint ( monoarthritis) |
| Symmetry | Symmetrical, meaning that joint symptoms on one side of the body will often be mirrored on the other side of the body | Can be either asymmetrical (unilateral) or symmetrical, particularly if many joints are involved |
| Fatigue, Malaise, Fever | Common due to systemic (whole-body) inflammation | Not typically associated with this disease, as it is not inflammatory |
| Morning Stiffness | Lasts more than 30 minutes and sometimes more than an hour, but improves with activity | Brief; less than 15 minutes |
Your provider will look for small, firm bumps (nodules) that often develop under the skin in people with RA. They also check for signs that RA has spread beyond the joint, often involving your skin, heart, and lungs.
In addition to evaluating your physical symptoms, your healthcare provider will review your family history. Rheumatoid arthritis often runs in families, tripling your risk if an immediate family member (parent, sibling, or child) has the condition. However, many people with a family history don’t develop RA, and having a family history doesn’t mean you’re destined to have it.
Lab Tests
Lab tests are used to classify your serostatus and measure the level of inflammation in your body:
Serostatus
Serostatus (loosely translated as “blood status”) refers to the key identifiers (biomarkers) of the disease in your blood. Your healthcare provider will run blood tests, looking for the primary biomarkers of RA: rheumatoid factor (RF) and anti-cyclic citrullinated peptide.
- Rheumatoid Factor (RF): RF is a type of autoantibody found in approximately 70% of people living with RA. Autoantibodies are proteins produced by the immune system that attack healthy cells or cell products as if they were germs. While high levels of RF are strongly suggestive of RA, they also can occur with other autoimmune diseases like lupus or non-autoimmune disorders such as cancer and chronic infections.
- Anti-Cyclic Citrullinated Peptide (anti-CCP): Anti-CCP is another autoantibody found in the majority of people with rheumatoid arthritis. Unlike RF, a positive anti-CCP test result occurs almost exclusively in people with RA. A positive result might even identify people who are at risk for getting the disease, such as those with a family history of it.
Because neither test is 100% indicative of RA, they’re used as part of the diagnostic process rather than as sole indicators.
When running blood tests for RA serostatus, lab technicians often use two techniques:
- RA latex turbid test: The RA latex turbid test (latex agglutination assay) mixes your blood sample with latex beads coated with RF antibodies. The beads cluster together if the antibodies are present.
- Quantitative nephelometry: In a quantitative nephelometry test, your blood sample is placed on a plate containing an antigen. If your blood contains RF antibodies, they bind with the antigens RF factors.
Serostatus Lab Test Results
The normal range for the RF test is 20 IU/ml or less. Test results above 20 IU/ml are considered positive for rheumatoid factor. However, about 20% of people with RA test negative for RF and about 5% of people who test positive for RF do not have RA.
Anti-CCP test results less than 20 units (20 EU/ml) indicate you don’t have RA. Those above 20 units suggest RA. The higher the number, the more likely you are to have the condition. A negative anti-CCP test doesn’t rule out RA, as about 20% of RA patients are seronegative for anti-CCP.
Inflammatory Markers
Inflammation is a defining characteristic of rheumatoid arthritis, and certain markers in your blood reveal information about inflammation to your healthcare provider. Tests that look at key markers not only help confirm the initial RA diagnosis but are used periodically to see how well you’re responding to treatment.
Two common tests of inflammatory markers include the following:
- Erythrocyte sedimentation rate (ESR or sed rate) is a test that measures how long it takes red blood cells to settle to the bottom of a long, upright tube, known as a Westergren tube. When there’s inflammation, the red blood cells stick together and sink faster. It is a non-specific measurement of inflammation but can provide key insights that are valuable to a diagnosis.
- C-reactive protein (CRP) is a type of protein the liver produces in response to inflammation. While also non-specific, it is a more direct measure of your inflammatory response.
ESR and CRP can also be used to diagnose arthritis remission, a state of low disease activity in which inflammation is more or less in check.
Your healthcare provider may order other tests to gauge your disease progression, as well.
Imaging Tests
The role of imaging tests in rheumatoid arthritis is to identify the signs of joint damage, including bone and cartilage erosion and the narrowing of the joint spaces. They can also help track the progression of the disease and establish when surgery is needed.
Each test can provide different and specific insights:
- X-rays: Especially useful in identifying bone erosion and joint damage, X-rays are considered the primary imaging tool for arthritis. However, they’re not as helpful in the very early stages of the disease, before changes in cartilage and synovial tissues are significant.
- Magnetic resonance imaging (MRI): MRI scans are able to look beyond the bone, spot changes in soft tissues, and even positively identify joint inflammation in the early stages of the disease.
- Ultrasounds: These scans are also better than X-rays at spotting early joint erosion, and they can reveal specific areas of joint inflammation. This is a valuable feature, given that inflammation can sometimes linger even when the ESR and CRP point to remission. In such cases, treatment is continued until you’re truly in remission.
Rheumatoid Arthritis Doctor Discussion Guide
Get our printable guide for your next appointment to help you ask the right questions.
:max_bytes(150000):strip_icc()/DoctorDiscussionGuideOldMan-5c3e5dd446e0fb00017d6d47.png)
Classification Criteria
In 2010, the American College of Rheumatology (ACR) updated its longstanding classification criteria for rheumatoid arthritis. The revisions were motivated, in part, by advances in diagnostic technologies. While the classifications are intended to be used for clinical research purposes, they help healthcare providers be more certain about your diagnosis.
The 2010 ACR/EULAR Classification Criteria looks at four different clinical measures and rates each one on a scale of 0 to 5. A cumulative score of 6 to 10 can provide a high degree of confidence that you do, in fact, have rheumatoid arthritis.
While healthcare providers are the only ones who use these criteria, looking at them can help you understand why an RA diagnosis often can’t be made quickly or easily.
| Criteria | Value | Points |
| Duration of Symptoms | Less than six weeks | 0 |
| More than six weeks | 1 | |
| Joint Involvement | One large joint | 0 |
| Two to 10 large joints | 1 | |
| One to three small joints (without the involvement of larger joints) | 2 | |
| Four to 10 small joints (without the involvement of larger joints) | 3 | |
| Over 10 joints (with at least one small joint) | 5 | |
| Serostatus | RF and anti-CCP are negative | 0 |
| Low RF and low anti-CCP | 2 | |
| High RF and high anti-CCP | 3 | |
| Inflammatory Markers | Normal ESR and CRP | 0 |
| Abnormal ESR and CRP | 1 |
Progression
The strongest indicator of progressive joint damage in rheumatoid arthritis is considered to be seropositivity. That said, seronegativity doesn’t preclude progressive joint damage. Additionally, people who test positive for both rheumatoid factor and anti-CCP are more likely to have a rapid progression of joint damage than people who are positive for one or the other.
Factors that point to a poor prognosis with progressive joint damage include:
- X-ray evidence or clinical evidence of joint damage
- Increased number of joints involved with active synovitis (inflamed synovial tissues), tenderness, swelling, or joint effusions
- Elevated ESR or CRP
- Positive for anti-CCP
- High level of medication use, including corticosteroids, used to treat inflammation in the affected joints
- An inadequate response to medications
- Decreased joint function as determined by the Health Assessment Questionnaire
- Declining quality of life
Remission
Diagnosing disease remission is just as or more challenging than your initial RA diagnosis. It requires not only the full exam and testing but also a subjective assessment of your symptoms and how you feel.
Accurately diagnosing remission is important because it determines whether certain treatments can be stopped or if going off of them is likely to cause a relapse.
To this end, the ACR has established what is called the DAS28. DAS is an acronym for “disease activity score,” while 28 refers to the number of joints that are examined in the assessment.
The DAS involves four scores:
- The number of tender joints your healthcare provider finds (out of 28)
- The number of swollen joints your healthcare provider finds (out of 28)
- Your ESR and CRP results (normal versus abnormal)
- Your rating of how you feel and your overall health, ranging from “very good” to “very bad”
These results are put through a complex mathematical formula to calculate your overall score.
| DAS 28 SCORES | |
|---|---|
| 0–2.5 | Remission |
| 2.6–3.1 | Low disease activity |
| 3.2–5.1 | Moderate disease activity |
| Above 5.1 | High disease activity |
Conditions With Similar Symptoms
Just as certain tests can help differentiate between rheumatoid arthritis and osteoarthritis, other tests may be ordered to find out whether your symptoms could be caused by another condition. This is especially likely if your RA test results are either inconclusive or negative.
Conditions with similar symptoms include other autoimmune disorders as well as connective tissue, neurological, and chronic inflammatory diseases such as:
Summary
Diagnosing rheumatoid arthritis involves several steps to identify signs of the disease and rule out other conditions that cause similar symptoms. Your healthcare provider does a comprehensive physical exam, paying particular attention to your joints and looking for inflammation and swelling in the same joints on both sides of your body.
Your provider runs lab tests that pick up RA biomarkers and signs of inflammation. They may also do various tests to rule out other health conditions. Diagnostic imaging is the final step. Your healthcare provider may take X-rays. However, MRI and ultrasound images uniquely help diagnose RA. They can show the earliest signs of RA and the severity of joint damage.
:max_bytes(150000):strip_icc()/CarolEustice_660-13556acdcfe048b1bf6f59a87cc86d99.jpg)
اكتشاف المزيد من LoveyDoveye
اشترك للحصول على أحدث التدوينات المرسلة إلى بريدك الإلكتروني.