From the Guidelines
The workup for Systemic Lupus Erythematosus (SLE) should include a comprehensive panel of laboratory tests and clinical evaluation, prioritizing the assessment of disease activity, organ damage, and comorbidities, as recommended by the European League Against Rheumatism (EULAR) 1. The initial evaluation should begin with a complete blood count, comprehensive metabolic panel, urinalysis, and inflammatory markers like ESR and CRP.
- Specific autoantibody tests are essential, including:
- ANA (antinuclear antibody), which is positive in over 95% of SLE patients
- Anti-dsDNA
- Anti-Smith antibodies
- Anti-Ro/SSA
- Anti-La/SSB
- Anti-RNP antibodies
- Complement levels (C3, C4) should be measured as they are often decreased in active disease.
- Additional tests include:
- Antiphospholipid antibodies
- Direct Coombs test
- 24-hour urine protein if kidney involvement is suspected Imaging studies like chest X-ray or echocardiogram may be needed based on symptoms.
- Tissue biopsies (skin, kidney) can confirm organ involvement. This comprehensive approach is necessary because SLE is a multisystem autoimmune disease with varied presentations, and diagnosis requires meeting classification criteria that combine clinical features with laboratory findings, as outlined in the EULAR recommendations 1. The assessment of patients with SLE should also include the evaluation of cardiovascular risk factors, osteoporosis, cancer, and infection risk, as well as the monitoring of disease activity and organ damage, as recommended by the EULAR guidelines 1. The use of a standardized core set of variables for the assessment and monitoring of patients with SLE is recommended, including the measurement of ANA, anti-dsDNA, and anti-ENA antibodies, as well as the assessment of disease activity and organ damage 1.
From the Research
Diagnostic Criteria for Systemic Lupus Erythematosus (SLE)
- The 2019 European Alliance of Associations for Rheumatology/American College of Rheumatology classification criteria are estimated to be 96.1% sensitive and 93.4% specific for SLE 2
- These criteria include clinical factors such as fever, cytopenia, rash, arthritis, and proteinuria, as well as immunologic measures like SLE-specific autoantibodies and low complement levels 2
- The Systemic Lupus Collaborating Clinics proposed the SLICC criteria for SLE in 2012, which take into account new knowledge of autoantibodies and the importance of low complement 3
Laboratory Tests for SLE
- Antinuclear antibody (ANA), anti-double-stranded DNA antibody (anti-dsDNA), and anti-mutated citrullinated vimentin antibody (anti-MCV) are important serologic markers for SLE 4
- Cell-bound complement activation products, such as complement C4d levels on erythrocytes (EC4d), platelets (PC4d), and B cells (BC4d), can enhance diagnostic performance in SLE 4
- Complement receptor 1 levels on erythrocytes (ECR1) can also be useful in diagnosing SLE 4
Assessment of SLE
- Accurate physical and laboratory diagnosis is crucial for the assessment of SLE 5
- Monitoring of disease activity, recording of accumulated organ morbidity, and integration of these with the patient's own perceptions of health status and quality of life are essential components of SLE assessment 5
- The primary goal of treatment is to achieve disease remission or quiescence, defined by minimal symptoms, low levels of autoimmune inflammatory markers, and minimal systemic glucocorticoid requirement while the patient is treated with maintenance doses of immunomodulatory or immunosuppressive medications 2