SLE diagnostic criteria
Formal Definition
The 2019 European League Against Rheumatism (EULAR) / American College of Rheumatology (ACR) classification criteria for systemic lupus erythematosus (SLE) — a weighted, multidisciplinary criteria system used to classify patients for research and clinical diagnosis; requires a positive ANA (≥1:80 on HEp-2 cells) as an entry criterion, with subsequent additive weighted criteria across seven domains: constitutional (fever), hematologic (leukopenia, thrombocytopenia, autoimmune hemolysis), neuropsychiatric (delirium, psychosis, seizure), mucocutaneous (oral ulcers, alopecia, subacute cutaneous, discoid, acute cutaneous), serosal (pleural/pericardial effusion, acute pericarditis), musculoskeletal (joint involvement), renal (proteinuria, renal biopsy Class II/III/IV/V lupus nephritis), and antiphospholipid antibodies (anticardiolipin, anti-β2GP1, lupus anticoagulant), plus low complement (C3/C4), and SLE-specific antibodies (anti-dsDNA, anti-Sm); a total score ≥10 is required for classification.
How It's Used on the Ward
"SLE criteria" or "lupus criteria" — the formal scoring system to diagnose lupus; you need ANA positive plus enough weighted points across multiple organ systems; the old criteria emphasized 4 of 11 findings, the 2019 update uses a weighted point system that's more sensitive for early disease but requires ANA as entry point.
Example
""34-year-old Black woman presents with 4 weeks of fatigue, malar rash, oral ulcers on hard palate, bilateral symmetric polyarthralgias (wrists and MCPs), and trace proteinuria on UA. ANA positive 1:1280 homogeneous pattern, anti-dsDNA positive 1:320, anti-Smith positive, C3 52 (low), C4 8 (low). UA: 2+ protein, Cr 0.9. Score breakdown: ANA entry (criterion met), acute cutaneous lupus (malar rash — 6 points), oral ulcers (2), joint involvement (6), proteinuria (4), low C3/C4 (4), anti-dsDNA (6), anti-Smith (6). Total score: 36. Criteria for SLE classification met. Started hydroxychloroquine, rheumatology referral for management.""
Clinical Context
Evolution of criteria: 1982 ACR (11 criteria, 4 needed); 1997 update (added antiphospholipid); 2012 SLICC (Systemic Lupus International Collaborating Clinics; more sensitive, required 4 criteria including at least 1 clinical and 1 immunologic OR biopsy-proven lupus nephritis with positive ANA/anti-dsDNA); 2019 EULAR/ACR — current standard, weighted point system. ANA entry: ANA must be ≥1:80 titer; if negative, the criteria cannot be satisfied (very high negative predictive value — there are rare ANA-negative SLE cases but the criteria start with the requirement). Weighted scoring: criterion points range from 2 to 10 depending on specificity; SLE-specific findings (biopsy-proven nephritis, anti-dsDNA, anti-Smith) carry higher weight. Threshold: ≥10 points classifies as SLE. Common clinical scenarios that meet criteria: malar rash (6) + joint (6) + ANA entry + anti-dsDNA or anti-Smith = 14+ — easy threshold. Limitations: criteria are classification criteria, not diagnostic criteria — some patients with clinical SLE may score <10; clinical judgment still matters. Pediatric, drug-induced, and overlap syndromes have additional considerations.