Fig 1: Compared the diagnostic performance of a combination of D-dimer and C4 with that of the biomarkers of hematological abnormalities for lupus activity by using receiver operating characteristic curvesClinical data were collected from the medical records of patients hospitalized with systemic lupus erythematosus (n = 2025). (A) D-dimer combined with C4 provided better diagnostic performance than D-dimer or C4 alone; (B) D-dimer combined with C4 provided better diagnostic performance than low C3, leukopenia, thrombocytopenia, high ESR, high FIB, or high CRP alone; (C) D-dimer combined with C4 provided better diagnostic performance than anti-dsDNA, anti-Sm, anti-SSA/Ro, anti-SSB/La, anti-RNP or anti-Rib P alone; (D) D-dimer combined with C4 provided better diagnostic performance than a combination of C3 and anti-dsDNA. Low C3 is defined as < 0.85 mg/mL; high FIB is defined as > 4.00 ug/mL; high ESR is defined as > 20.00 mm/h; high CRP is defined as > 8.00 mg/L. FIB, fibrinogen; ESR, erythrocyte sedimentation rate; CRP, C-reactive protein. Lupus activity was defined as systemic lupus erythematosus disease activity index score = 8.