Rheumatoid Arthritis Workup
The workup for rheumatoid arthritis requires documenting symmetric polyarthritis (especially hands and feet), obtaining RF and anti-CCP antibodies, measuring inflammatory markers (ESR/CRP), and performing baseline radiographs of hands and feet. 1
Clinical Assessment
History and Physical Examination
Document the following key clinical features:
- Symmetric joint swelling and tenderness, particularly in metacarpophalangeal (MCP), proximal interphalangeal (PIP), wrist, and metatarsophalangeal (MTP) joints 1, 2
- Morning stiffness lasting ≥1 hour before maximal improvement—this is a characteristic symptom that distinguishes inflammatory from mechanical arthritis 1, 2
- Duration of symptoms—early diagnosis within the first few months is critical to prevent irreversible joint damage 3
- Pattern of joint involvement—any appendicular joint can be affected, but distal interphalangeal joints, sacroiliac joints, and lumbar spine are rarely involved 2
Examine for extra-articular manifestations:
- Subcutaneous rheumatoid nodules (indicate severe disease) 1
- Interstitial lung disease 1
- Vasculitis 1
- Inflammatory eye disease 1
Common pitfall: Patients may present atypically—approximately 25% have acute or subacute onset, and some present with palindromic (recurrent oligoarthritis), monoarticular, or polymyalgia-like patterns 2. Don't dismiss RA based on atypical presentation.
Laboratory Testing
Serologic Markers
Order the following antibody tests:
- Anti-citrullinated protein antibody (ACPA/anti-CCP): High specificity (90%) with moderate sensitivity (60%) 1
- Rheumatoid factor (RF): Lower specificity (70%) with comparable sensitivity to ACPA 1
Both tests should be obtained as they provide complementary diagnostic information and prognostic value 1, 4.
Inflammatory Markers
Measure acute phase reactants:
- C-reactive protein (CRP): Strictly correlated with clinical assessment and radiographic changes 2
- Erythrocyte sedimentation rate (ESR): Provides information about acute phase response 1, 2
These markers are essential for assessing disease activity and monitoring treatment response 1, 4.
Imaging Studies
Baseline Radiographs
Obtain plain radiographs of hands and feet to document baseline structural damage 2. Early radiographic features include:
Consider additional imaging modalities:
- Ultrasonography: Can detect synovial thickening even in finger joints before radiographic changes appear, improving early assessment 2
- MRI, CT, or scintigraphy: Reserved for selected patients to assess extent of anatomic damage 2
Disease Activity Assessment
Establish baseline disease activity using validated composite measures before initiating treatment 5:
- Clinical Disease Activity Index (CDAI): Does not require laboratory values 5, 1
- Simplified Disease Activity Index (SDAI): Includes CRP 5, 1
- Disease Activity Score 28 (DAS28): Widely used in clinical trials 5, 4
Define disease activity states 1:
- Remission: SDAI ≤3.3 or CDAI ≤2.8
- Low disease activity: SDAI ≤11 or CDAI ≤10
These measurements are essential for implementing a treat-to-target approach and should be repeated every 1-3 months during active disease 1.
Functional Assessment
Document baseline functional status using patient-reported outcome measures to track disability and quality of life over time 6. This provides critical information about treatment effectiveness beyond disease activity measures.
Pre-Treatment Screening
Before initiating DMARDs, complete the following:
- Tuberculosis screening: Test for latent TB infection with tuberculin skin test or interferon-gamma release assay 5, 7
- Hepatitis B and C screening: Required before starting immunosuppressive therapy 5
- Complete blood count, liver function tests, creatinine: Baseline values needed for monitoring DMARD toxicity 5
- Pregnancy test in women of childbearing potential 5
Ensure age-appropriate vaccinations are current before starting immunosuppressive therapy 5, 7.
Timeline for Action
Treatment must be initiated within 3-6 months of symptom onset to prevent irreversible joint damage 1, 3. Early aggressive treatment can avert or substantially slow joint damage progression in up to 90% of patients 3. The workup should therefore be completed expeditiously to avoid delays in starting disease-modifying therapy.