Table 2. Youden’s index to diagnose COPD and cancer from healthy donors.

Analyte at 95% CI of mean	HD versus COPD	HD versus Cancer	COPD versus Cancer	CNM versus CM
VEGF >552.8 pg/ml (upper limit)	0.38 (70.6%)	0.10 (59.7%)	0.33 (65%)	0.28 (63%)
IL-8 <85.1 pg/ml (lower limit)	0.28 (66.2%)	0.55 (83.3%)	0.35 (71%)	0
MMP-9 >905.6 ng/ml (upper limit)	0.21 (60.3%)	0.17 (58.1%)	0.05 (51%)	0.03 (51.4%)

Youden’s index (scale of 0–1) was calculated as mentioned in materials and methods. The values in parentheses represent overall accuracy.