Laboratory Work to Investigate for Lupus

Core Autoantibody Panel

The European League Against Rheumatism (EULAR) recommends a comprehensive autoantibody panel at baseline, including ANA, anti-dsDNA, anti-Ro, anti-La, anti-RNP, anti-Sm, and anti-phospholipid antibodies, for the diagnosis of systemic lupus erythematosus (SLE) 1, 2
Anti-dsDNA antibodies correlate with disease activity and active renal disease, and changes in anti-dsDNA titres can be useful for monitoring disease progression 3, 4
Anti-Sm antibodies have prognostic value and are part of the baseline panel 1, 2
Anti-Ro (SSA) and anti-La (SSB) antibodies have prognostic value and are associated with neonatal lupus risk, making them essential before pregnancy 5, 6
Anti-RNP antibodies may provide prognostic information 7, 8
Anti-phospholipid antibodies are associated with thrombotic manifestations, damage development, and pregnancy complications, and should be re-evaluated before pregnancy, surgery, transplant, estrogen-containing treatments, or with new neurological/vascular events 1, 2, 3, 6

Baseline measurement of C3 and C4 is essential, and low complement levels (particularly C3) predict flares and correlate with active disease, especially in renal involvement 1, 2, 6

A complete blood count (CBC) is essential for detecting cytopenias, and severe anemia associates with organ involvement and worse prognosis 6, 3, 7, 8
Thrombocytopenia correlates with renal disease and progression to end-stage renal disease 6, 3
Severe leukopenia and lymphopenia increase infection risk 3, 4

ESR (erythrocyte sedimentation rate) is recommended at baseline and for monitoring 1, 2
CRP (C-reactive protein) has important clinical utility, but patients with SLE rarely have elevated CRP during disease flares, and significantly elevated CRP (>5-6 mg/dL) suggests superimposed infection with 80-84% specificity 6, 3

Serum creatinine (or eGFR) provides prognostic information about renal involvement 1, 6
Serum albumin levels indicate renal involvement and poor prognosis, with low levels being a negative prognostic factor 1, 6
Urinalysis with urine protein/creatinine ratio is essential for detecting and monitoring nephritis, and patients with persistently abnormal urinalysis or elevated creatinine should have urine microscopy and be considered for renal biopsy 1, 6