Analysis of Erythrocyte C4d to Complement Receptor 1 Ratio: Use in Distinguishing between Infection and Flare-Up in Febrile Patients with Systemic Lupus Erythematosus

Table 5

Receiver operating characteristic (ROC) curve analysis of the utility of the C4d/CR1 ratio in febrile SLE patients without infection.

Rules			Number(s)	Sensitivity (%)	Specificity (%)
A	C4d/CR1 > 1.2447	CRP > 4.67	0	0	0
		CRP < 4.67	21	84	87.5
	C4d/CR1 < 1.2447	CRP > 4.67	0	0	0
		CRP < 4.67	4	16	30.8
	Total		25
B	C4d/CR1 > 1.2447	CRP > 2.2	1	4	20.0
		CRP < 2.2	20	80	100.0
	C4d/CR1 < 1.2447	CRP > 2.2	2	8	13.3
		CRP < 2.2	2	8	28.6
	Total		25