What are the recommended tests and initial treatment for rheumatoid arthritis (RA)?

Recommended Tests and Initial Treatment for Rheumatoid Arthritis

The diagnosis of rheumatoid arthritis requires comprehensive laboratory testing including rheumatoid factor (RF), anti-citrullinated protein antibody (ACPA), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR), followed by early initiation of methotrexate as first-line therapy to prevent joint damage and disability. 1, 2

Diagnostic Testing for RA

Core Laboratory Tests

• Complete blood count with differential to assess for anemia and rule out other conditions 1, 2
• Inflammatory markers: ESR and/or CRP (CRP preferred as it's more reliable and not age-dependent) 1, 2
• Autoantibody testing: RF and ACPA (anti-CCP) - both should be ordered as they provide complementary diagnostic and prognostic information 1, 2
• Liver function tests (transaminases) and renal function assessment to establish baseline organ function before treatment 1
• Urinalysis to exclude other diseases 1
• Antinuclear antibodies (ANA) to help rule out other autoimmune conditions 1, 2

Clinical Assessment

• Joint examination remains the gold standard for detecting synovitis - look for joint swelling, pain, and morning stiffness lasting ≥1 hour 1
• Use of composite disease activity measures like DAS28, SDAI, or CDAI to quantify disease activity 1, 3
• In doubtful cases, ultrasound or MRI can help detect subclinical synovitis 1
• Baseline radiographs of hands and wrists to assess for erosions 2

Initial Treatment Approach

First-Line Therapy

• Methotrexate is the anchor drug and should be initiated early, typically at 7.5-15 mg weekly for RA, with dose escalation as needed 1, 4, 5
• Baseline laboratory testing must be performed before starting methotrexate, including complete blood count, liver and renal function tests 4, 5
• Patients should be clearly instructed that methotrexate is taken WEEKLY, not daily, as mistaken daily use has led to fatal toxicity 4

Adjunctive Therapies

• Systemic glucocorticoids (prednisone) can be used temporarily to reduce pain and swelling while waiting for DMARDs to take effect 1, 6
• Intra-articular glucocorticoid injections may provide relief for particularly symptomatic joints 1
• NSAIDs can be considered for symptom control after evaluating gastrointestinal, renal, and cardiovascular risk 1
• Caution when combining NSAIDs with methotrexate as they may reduce tubular secretion and enhance toxicity 4

Treatment Goals and Monitoring

Treatment Targets

• The goal is remission or low disease activity within 6 months 1, 6
• Treatment should be adjusted if significant improvement is not seen within 3 months 6
• Regular monitoring of disease activity using composite measures (DAS28, SDAI, CDAI) 1, 3

Laboratory Monitoring

• Hematology at least monthly during initial therapy 4
• Liver and renal function tests every 1-2 months 4
• More frequent monitoring during dose changes or periods of increased risk 4

Important Considerations and Pitfalls

• Early diagnosis and treatment (ideally within 6 weeks of symptom onset) is crucial to prevent irreversible joint damage 1, 6
• Up to 30-40% of RA patients may have negative RF or ACPA, or normal ESR/CRP - diagnosis should not rely solely on laboratory findings 7
• Avoid overreliance on a single test; the diagnosis is clinical, supported by laboratory findings 8, 7
• Patients taking biologic agents should be tested for hepatitis B, hepatitis C, and tuberculosis before initiating therapy 9
• Patient education about the disease, its treatment, and the importance of medication adherence is essential 1

Treatment Algorithm

1. Confirm diagnosis through clinical examination and laboratory testing
2. Start methotrexate (with folic acid supplementation) as first-line therapy
3. Consider short-term glucocorticoids for initial symptom control
4. Assess response after 3 months
5. If inadequate response, consider adding a second DMARD or biologic agent 6