Table 6.

Diagnostic characteristics of the per cent predicted method, using the percentile method as a reference standard using Crapo et al (5–7) and Gutierrez et al (12) equations for men (n=2176)

Parameter	Crapo et al						Gutierrez et al
	Sen, %	Spe, %	PPV, %	NPV, %	LR+	LR−	Sen, %	Spe, %	PPV, %	NPV, %	LR+	LR−
FEV1	93	97	98	91	32	0.07	98	90	92	97	9	0.03
FVC	99	90	84	99	10	0.01	95	94	93	96	17	0.05
RV↓	100	92	50	100	13	0.00	100	87	33	100	7	0.00
RV↑	82	100	100	91	2264	0.18	90	92	98	96	107	0.11
TLC↓	93	100	97	99	189	0.07	90	99	97	97	93	0.11
TLC↑	94	100	98	99	357	0.06	85	100	97	98	343	0.15
DLco	88	97	97	88	32	0.12	99	91	82	99	11	0.02

↓ Below normal;

↑ Above normal, for all other parameters, only below normal are presented; DLco Diffusing capacity of the lung for carbon monoxide; FEV₁ Forced expiratory volume in 1 s; FVC Forced vital capacity; LR+ Positive likelihood ratio; LR– Negative likelihood ratio; NPV Negative predictive value; PPV Positive predictive value; RV Residual volume; Sen Sensitivity; Spe Specificity; TLC Total lung capacity