Table 3.

Predictivity of anti-C1q antibodies in SLE flares

Number of patients (n)	Findings	Study
68	For renal flares: sensitivity 71%, specificity 92%, PPV 50%, NPV 97%	Siegert et al., 1993 [40]
151	10 of 14 patients who developed proliferative nephritis had significant increases in anti-C1q level	Coremans et al., 1995 [15]
151	NPV 100% for nephritis	Marto et al., 2005 [39]
70	For severe lupus nephritis: sensitivity 100%, specificity 95.7%, PPV 50%, NPV 100%	Meyer et al., 2009 [30]
23	For renal flares: sensitivity 75.7%, specificity 84%, PPV 56%, NPV 70%	Matrat et al., 2011 [29]

All anti-C1q antibodies were measured using enzyme-linked immunosorbent assays

NPV negative predictive value, PPV positive predictive value, SLE systemic lupus erythematosus