What is the workup for autoimmune problems?

Diagnostic Work-up for Autoimmune Diseases

The comprehensive diagnostic work-up for autoimmune diseases should include inflammatory markers, complete blood count, autoantibody panels, and organ-specific tests based on clinical presentation to accurately diagnose and monitor autoimmune conditions. 1

Initial Laboratory Evaluation

• Complete blood count (CBC) with differential is necessary to assess for cytopenias which are common in many autoimmune conditions 1, 2
• Inflammatory markers including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) should be evaluated to assess disease activity 1, 2
• Comprehensive metabolic panel including liver and kidney function tests should be performed to assess for organ involvement 1, 2
• Antinuclear antibody (ANA) testing should be used as a screening tool for many systemic autoimmune diseases 1
• Rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibodies should be tested for suspected inflammatory arthritis 1, 2

Disease-Specific Testing

• For suspected systemic lupus erythematosus, anti-dsDNA, anti-Smith, anti-RNP, anti-SSA, anti-SSB antibodies should be tested 2
• For suspected systemic sclerosis, anti-centromere, anti-Scl-70, anti-RNA polymerase III antibodies should be tested 2
• For suspected autoimmune hepatitis, anti-smooth muscle antibodies, anti-liver kidney microsomal antibodies, and serum immunoglobulins should be tested 3, 2
• For suspected myositis, creatine kinase (CK), transaminases (AST, ALT), lactate dehydrogenase (LDH), aldolase, and myositis-specific antibodies should be tested 3, 2
• For suspected autoimmune thyroid disease, thyroid function tests (TSH, free T4) and thyroid antibodies (anti-TPO, anti-thyroglobulin) should be tested 2

Organ-Specific Testing

• For inflammatory myopathies: CK, transaminases, LDH, aldolase, and troponin (to evaluate cardiac involvement) 3, 2
• For autoimmune hepatitis: liver function tests, serum immunoglobulins, and liver-specific autoantibodies 3, 2
• For chronic spontaneous urticaria: differential blood count, C-reactive protein/ESR, IgG-anti-TPO, and total IgE levels 3
• For pulmonary alveolar proteinosis: GM-CSF antibody testing is recommended for all patients with suspected or confirmed PAP syndrome 3

Imaging Studies

• Joint radiographs should be performed for suspected inflammatory arthritis 1
• Abdominal ultrasound or CT scan should be performed to evaluate for organomegaly in suspected systemic disease 1
• Muscle MRI should be performed for suspected inflammatory myopathies 3, 1
• For pulmonary involvement, chest imaging (X-ray or CT) should be performed 3

Additional Diagnostic Procedures

• For suspected autoimmune hepatitis, liver biopsy is considered essential for definitive diagnosis 3, 1
• For suspected pulmonary alveolar proteinosis, bronchoalveolar lavage (BAL) should be performed as part of the diagnostic work-up 3
• For suspected myositis with uncertain diagnosis, electromyography (EMG), MRI, and/or muscle biopsy should be considered 3

Pre-Treatment Testing

• Testing for latent tuberculosis, hepatitis B, and hepatitis C should be performed before starting immunosuppressive therapy, especially rituximab 3, 4
• Complement levels (C3, C4, CH50) should be tested for suspected lupus or complement deficiencies 2
• HLA typing (particularly HLA-B27) should be performed for suspected spondyloarthropathies 2

Common Pitfalls to Avoid

• Relying solely on autoantibody testing without clinical correlation can lead to misdiagnosis 1, 2
• Delaying treatment while awaiting complete diagnostic work-up in severe presentations can worsen outcomes 3, 1
• Not screening for infectious diseases (HIV, hepatitis, tuberculosis) before starting immunosuppressive therapy can lead to serious complications 3, 4
• Failing to monitor immunoglobulin levels in patients receiving rituximab, as hypogammaglobulinemia is a common side effect 4

Monitoring Disease Activity

• Regular monitoring of inflammatory markers (ESR, CRP) should be performed to assess treatment response 1, 2
• Disease-specific autoantibodies should be monitored to assess disease activity when appropriate 1
• Organ function tests should be monitored based on systems involved 1, 2
• For patients on rituximab therapy, immunoglobulin levels should be monitored due to risk of hypogammaglobulinemia 4