From the Guidelines
A diagnosis of Rheumatoid Arthritis (RA) should be considered in patients presenting with joint swelling, pain, or stiffness, and a referral to a rheumatologist within 6 weeks is recommended for early assessment and management. According to the 2016 update of the EULAR recommendations for the management of early arthritis 1, clinical examination is the primary method for detecting arthritis, which may be confirmed by ultrasonography.
Key Diagnostic Tests
The following tests are typically included in an arthritis panel to diagnose and monitor RA:
- Rheumatoid factor (RF)
- Anti-cyclic citrullinated peptide (anti-CCP) antibodies
- Erythrocyte sedimentation rate (ESR)
- C-reactive protein (CRP)
- Antinuclear antibodies (ANA)
- Complete blood count (CBC)
These tests help distinguish between different forms of arthritis and inflammatory conditions. The rheumatoid factor and anti-CCP tests are particularly useful for diagnosing RA, while ESR and CRP measure inflammation levels in the body 1.
Interpretation of Results
Results of the arthritis panel should be interpreted alongside clinical symptoms and physical examination findings, as no single test is definitive for diagnosing arthritis. Regular monitoring with these tests can also help assess disease activity and treatment effectiveness in patients with established arthritis.
Management
The main goal of treatment is to achieve clinical remission, and regular monitoring of disease activity, adverse events, and comorbidities should guide decisions on choice and changes in treatment strategies 1. Non-pharmacological interventions, such as dynamic exercises and occupational therapy, should be considered as adjuncts to drug treatment in patients with early arthritis. Patient education and counseling on disease management, lifestyle modifications, and treatment options are also essential for optimal outcomes.
From the FDA Drug Label
The results of all four trials were expressed in percentage of patients with improvement in RA using ACR response criteria Study I evaluated 234 patients with active RA who were ≥ 18 years old, had failed therapy with at least one but no more than four disease-modifying antirheumatic drugs (DMARDs) Patients had ≥ 12 tender joints, ≥ 10 swollen joints, and either erythrocyte sedimentation rate (ESR) ≥ 28 mm/hr, C-reactive protein (CRP) > 2. 0 mg/dL, or morning stiffness for ≥ 45 minutes.
The diagnosis for a patient undergoing an arthritis (Rheumatoid Arthritis) panel is Rheumatoid Arthritis (RA), characterized by:
- Active RA
- Failed therapy with at least one disease-modifying antirheumatic drug (DMARD)
- Clinical criteria, including:
- ≥ 12 tender joints
- ≥ 10 swollen joints
- Erythrocyte sedimentation rate (ESR) ≥ 28 mm/hr
- C-reactive protein (CRP) > 2.0 mg/dL
- Morning stiffness for ≥ 45 minutes 2
From the Research
Diagnosis of Rheumatoid Arthritis
The diagnosis of rheumatoid arthritis (RA) is based on a combination of clinical features, laboratory tests, and medical history. The criteria for diagnosis include:
- Having at least one joint with definite swelling that is not explained by another disease 3, 4
- The presence of a rheumatoid factor or anti-citrullinated protein antibody, or elevated C-reactive protein level or erythrocyte sedimentation rate suggests a diagnosis of rheumatoid arthritis 3, 4
- The likelihood of a rheumatoid arthritis diagnosis increases with the number of small joints involved 3
Laboratory Tests
Laboratory tests used to diagnose rheumatoid arthritis include:
- Rheumatoid factor (RF) 3, 4, 5, 6
- Anti-cyclic citrullinated peptide (anti-CCP) antibody 5, 6
- C-reactive protein (CRP) 3, 4, 6
- Erythrocyte sedimentation rate (ESR) 3, 4, 6
- Complete blood count with differential and assessment of renal and hepatic function 3
Diagnostic Performance of Anti-CCP Antibody
The anti-CCP antibody test has high specificity for rheumatoid arthritis, with a specificity of 98% 6. It can be detected early in the disease process and is useful in identifying patients who are likely to have severe disease and irreversible damage 5. However, its sensitivity is low, and a negative result does not exclude disease 5.
Prognostic Capability of Anti-CCP Antibody
The presence or absence of anti-CCP antibody can be used to predict the prognosis and treatment outcome after disease-modifying antirheumatic drugs (DMARDs) or biological therapy 6. The titer of anti-CCP can also be used to predict the severity of the disease 6.