Table 2.

Sensitivity and specificity of the C3-dominant or -isolated criteria on IF to capture the presence of intramembranous electron-dense deposits, LPVs, and/or C3NeF and low serum C3 and normal C4 in patients with C3G/MPGN

Categories	Prevalence		P Value	C3G
Categories	C3G	IC-MPGN	P Value	Sensitivity, %	Specificity, %
All patients
Intramembranous electron-dense deposits	0.27	0.04	<0.001	89	53
LPVs and/or C3NeF	0.64	0.49	0.07	59	56
Low serum C3 and normal C4	0.78	0.70	0.23	56	55
Only patients with C3G and isolated C3 versus patients with IC-MPGN and 3+ staining in any of Ig or C1q^a
Intramembranous electron-dense deposits	0.24	0.03	0.03	89	56
LPVs and/or C3NeF	0.53	0.47	0.62	52	55
Low serum C3 and normal C4	0.76	0.68	0.46	52	58

↵a Patients with C3G and 3+ C3 staining and no Ig or C1q staining on IF and patients with IC-MPGN and 3+ staining in at least one of the Igs or C1q.