Table 3.

Values for sensitivity, specificity, predictive values and likelihood ratio for detecting obstructions (FEV1/FVC < 0.7 by spirometry) for two cutoff points of the FEV1/FEV6 ratio measured with the Vitalograph COPD-6

FEV1/FEV6	Sensitivity%	Specificity %	PPV%	NPV%	+ LR	−LR
<0.7	88%	98	89	97	42	0.16
<0.72	84	97	84	97	28	0.16