Comparative Study of Circulating MMP-7, CCL18, KL-6, SP-A, and SP-D as Disease Markers of Idiopathic Pulmonary Fibrosis

Table 2

Cut-off values and the discriminatory ability of five biomarkers by ROC curve analysis, which distinguishes IPF patients () from control subjects ().

	MMP-7	CCL18	KL-6	SP-A	SP-D
AUC	0.9638	0.7036	0.9957	0.7865	0.9242
95% CI	0.9374–0.9901	0.6275–0.7815	0.9898–1.0020	0.7229–0.8501	0.8866–0.9619
Cut-off value	5.56 ng/mL	38.7 ng/mL	476 U/mL	44.0 ng/mL	107.0 ng/mL
Sensitivity	87.7%	66.2%	96.9%	66.2%	84.6%
Specificity	93.2%	67.4%	98.5%	76.5%	88.6%
Diagnostic accuracy	91.4%	67.0%	98.0%	73.1%	87.3%
Likelihood ratio	12.9	2.0	64.0	2.8	7.5

ROC: receiver operating characteristic, IPF: idiopathic pulmonary fibrosis, MMP-7: matrix metalloproteinase-7, CCL18: CC-chemokine ligand 18, KL-6: Krebs von den Lungen-6, SP-A: surfactant protein-A, SP-D: surfactant protein-D, AUC: area under the curve, and 95% CI: 95% confidence interval.
Control subjects consisted of 31 patients with bacterial pneumonia and 101 healthy controls.