Table 2.

Diagnostic performance of the determination of the three complement C4-derived fragments in plasma samples from early-stage lung cancer

Diagnostic parameters*	C4d-containing fragments	C4d	C4c
Sensitivity (%)	92 (79–98)	79(64–91)	72 (55–85)
Specificity (%)	44 (28–60)	82 (66–92)	95 (83–99)
Accuracy (%)	68 (56–78)	81 (70–89)	83 (73–91)
Positive predictive value (%)	62 (55–69)	82 (69–90)	93 (78–98)
Negative predictive value (%)	85 (64–95)	80 (68–88)	77 (67–85)
Positive likelihood ratio	1.64(1.22–2.19)	4.43 (2.22–8.83)	14.00 (3.58–54.78)
Negative likelihood ratio	0.18(0.06–0.55)	0.25(0.13–0.47)	0.30(0.18–0.49)

^*Diagnostic parameters were calculated using the cut-off that provides the maximum Youden index. 95% CIs are also shown.