From the Guidelines
The diagnostic criteria for Systemic Lupus Erythematosus (SLE) are based on the 2019 European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification system, which requires a positive antinuclear antibody (ANA) at a titer of ≥1:80 as an entry criterion, plus accumulation of 10 or more points across clinical and immunological domains.
Key Criteria
The clinical criteria include:
- Constitutional symptoms (fever)
- Hematologic abnormalities (leukopenia, thrombocytopenia, autoimmune hemolysis)
- Neuropsychiatric manifestations
- Mucocutaneous features (oral ulcers, non-scarring alopecia, malar rash, discoid rash)
- Serositis (pleural or pericardial effusion)
- Joint involvement (synovitis in two or more joints) The immunological criteria include:
- Elevated anti-dsDNA antibodies
- Anti-Smith antibodies
- Antiphospholipid antibodies
- Low complement levels (C3, C4)
- Direct Coombs test ### Importance of ANA As noted in the study by 1, the introduction of a positive ANA result as a required entry criterion in the SLE classification has improved the performance of the criteria as a classification system. However, it is essential to exercise caution when using these criteria for diagnosis due to the relatively low specificity of ANA detection for SLE, as highlighted in 2.
Clinical Judgment
Diagnosis ultimately requires clinical judgment, considering the patient's complete presentation, as SLE can affect multiple organ systems with varying severity and manifestations over time. The EULAR/ACR 2019 classification system helps clinicians distinguish SLE from other autoimmune conditions, but it is crucial to remember that this system is primarily used for classification purposes, and its application in clinical practice should be done with careful consideration of the patient's overall clinical picture.
From the Research
Diagnostic Criteria for Systemic Lupus Erythematosus (SLE)
The diagnostic criteria for SLE are based on a combination of clinical and serological findings. According to 3, the American College of Rheumatology (ACR) criteria, which were first proposed in 1971 and revised in 1982 and 1997, include clinical manifestations such as skin lesions, arthritis, renal disorder, neurologic disorder, hematologic changes, and others. Serum anti-nuclear antibody, anti-ds-DNA antibody, and anti-Sm antibody are important biomarkers of SLE patients.
Classification Criteria
There are several classification criteria for SLE, including:
- The 1997 American College of Rheumatology (ACR'97) criteria 4
- The 2012 Systemic Lupus International Collaborating Clinics (SLICC'12) criteria 4
- The 2019 European League Against Rheumatism/American College of Rheumatology (EULAR/ACR'19) criteria 4, 5
Key Points
- The ACR criteria have undergone several revisions, with the most recent being the EULAR/ACR'19 criteria 4, 5
- The SLICC'12 criteria performed best among the original three criteria in distinguishing patients with SLE from patients with pure mucocutaneous manifestations (isolated cutaneous lupus erythematosus without internal disease, i-CLE) 4
- A positive ANA is an important entry criterion for the diagnosis of SLE 4
- The EULAR/ACR'19 criteria enable earlier and more accurate classification of SLE 5
Clinical Manifestations
Some common clinical manifestations of SLE include: