C3 and systemic lupus erythematosus: In differentiating ANA- SLE from ARD (Figure 2D), TC4d (AUC: 0.66) significantly outperformed C3 (0.61, p =0.04), anti-dsDNA (0.41 p <0.01), anti-Smith (0.38, p <0.01) while performances against all other biomarkers were not significantly different.