What are the recommended screening tests for rheumatic diseases?

Screening Tests for Rheumatic Diseases

For patients with systemic autoimmune rheumatic diseases at risk for interstitial lung disease (the major life-threatening complication), screen with both high-resolution computed tomography (HRCT) of the chest and pulmonary function tests (PFTs including spirometry, lung volumes, and DLCO), while for general rheumatic disease diagnosis, obtain antinuclear antibody (ANA) with titer and pattern, rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) antibodies, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP). 1, 2, 3

Screening for Interstitial Lung Disease in High-Risk Rheumatic Diseases

The most critical screening priority in rheumatic diseases is detecting interstitial lung disease (ILD), which is the leading cause of death in systemic sclerosis and a major cause of mortality in rheumatoid arthritis. 1

Who Requires ILD Screening

Screen all patients with the following conditions: 1

• Systemic sclerosis (SSc) - highest priority, affects >50% of patients
• Idiopathic inflammatory myopathies (IIM) - including dermatomyositis, polymyositis, anti-synthetase syndrome
• Rheumatoid arthritis (RA) with risk factors: high-titer RF or anti-CCP, smoking history, older age at onset, male sex 1
• Mixed connective tissue disease (MCTD) 1
• Sjögren disease (SjD) with risk factors 1

Recommended ILD Screening Tests

Primary screening combination (conditionally recommended): 1

• HRCT chest - sensitivity 95.7%, specificity 63.8% for detecting ILD
• PFTs - must include spirometry, lung volumes, and DLCO (not just spirometry alone)

The combination of HRCT plus PFTs is superior to either test alone because PFTs alone miss cases (FVC <80% has only 47.5% sensitivity), and patients with early ILD can have normal PFTs or difficulty performing them. 1

Tests to avoid for ILD screening: 1

• Do NOT use chest radiography - inadequate sensitivity 1
• Do NOT use 6-minute walk distance (6MWD) - affected by arthritis and cardiac disease, not specific 1
• Do NOT use ambulatory desaturation testing alone - feasibility concerns in rheumatology practices 1
• Do NOT use bronchoscopy for routine screening - invasive, reserved for ruling out infection or alternative diagnoses 1
• Strongly avoid surgical lung biopsy for screening - excessive risk 1

Disease-Specific ILD Screening Algorithms

For Systemic Sclerosis (highest risk): 1

• Perform HRCT, PFTs (spirometry and DLCO), and 6MWD at diagnosis
• Risk stratify based on anti-Scl-70 positivity, diffuse cutaneous subtype, male sex, early disease (first 5-7 years) 1
• High-risk patients: PFTs every 6 months, annual HRCT for first 3-4 years 1
• Lower-risk patients: Annual PFTs, HRCT if symptoms or function worsen 1

For Rheumatoid Arthritis: 1

• All patients: baseline chest radiograph and PFTs (spirometry and DLCO) 1
• High-risk patients (high-titer RF/anti-CCP, smoking, male, older age): add HRCT 1
• With risk factors: Annual PFTs, HRCT every 2 years 1
• Without risk factors: PFTs only if symptomatic 1

General Serologic Screening for Rheumatic Diseases

Essential Autoimmune Panel

For initial rheumatic disease evaluation: 2, 3, 4

• Antinuclear antibody (ANA) with titer and pattern - screens for connective tissue diseases 2
• Rheumatoid factor (RF) - for rheumatoid arthritis, though 30-40% of RA patients are seronegative 3
• Anti-cyclic citrullinated peptide (anti-CCP) antibodies - more specific for RA than RF 2, 3
• ESR and CRP - assess inflammation, though 40% of RA patients have normal values 3

Disease-Specific Antibody Testing

When specific diseases are suspected: 2

• Anti-Scl-70 (anti-topoisomerase) - for systemic sclerosis-ILD 2
• Anti-Ro/SSA, anti-La/SSB, anti-Ro52 - for Sjögren syndrome-ILD 2
• Anti-Jo-1 and antisynthetase antibodies - for inflammatory myopathy-ILD 2
• Anti-DNA antibody - specific for systemic lupus erythematosus 4
• Anti-centromere antibody - for CREST syndrome of scleroderma 4

Critical Pitfalls to Avoid

Do not rely solely on laboratory tests for diagnosis - more than 30-40% of RA patients have negative RF or anti-CCP, and 40% have normal ESR or CRP, making clinical assessment paramount. 3

Do not skip HRCT in favor of PFTs alone - history and physical examination have poor sensitivity (dry cough 15% sensitive, crackles 69% sensitive) and PFTs alone miss nearly half of ILD cases. 1

Do not use CT angiogram studies for ILD assessment - these are performed in incomplete inspiration and can obscure, accentuate, or mimic ILD. 1

Do not screen all RA patients with HRCT - given RA's high prevalence (3-5% develop ILD), reserve HRCT for those with risk factors or abnormal baseline screening. 1

Monitoring Established ILD

For patients with confirmed SARD-ILD: 1

• IIM-ILD and SSc-ILD: PFTs every 3-6 months for first year, then less frequently when stable 1
• RA-ILD, SjD-ILD, MCTD-ILD: PFTs every 3-12 months for first year, then less frequently when stable 1
• HRCT when clinically indicated - no specific routine interval recommended 1
• Ambulatory desaturation testing every 3-12 months 1