TABLE 1

Summary of Caucasian data included in the Global Lung Function Initiative transfer factor of the lung for carbon monoxide reference values

Country	Subjects	Equipment	Altitude m	Anatomic V_D	Breath-hold calculation	Reported values	Caucasian %	Obese %	FEV₁ z-score
New Zealand	71	SensorMedics Vmax Encore	20	Fixed	Jones–Meade	Average	100	18.30	−0.31±0.9
Australia	605	Other	8	Fixed	Jones–Meade	Average	100	18.40	0.56±1.0
Australia	120	SensorMedics Vmax Encore	10	Fixed	Jones–Meade	Average	100	8.30	0.25±0.9
Spain	430	Jaeger MasterScreen	710	Body size adjusted	Jones–Meade	Average	100	27.90	−1.0±1.3
The Netherlands	543	Jaeger MasterScreen	13	Fixed	Unknown	Automated	100	3.00	NR
USA	300	SensorMedics Vmax Encore	222	Body size adjusted	Jones–Meade	Average	100	9.00	0.03±0.9
USA	1302	Collins	50	Body size adjusted	Jones–Meade	Automated	100	18.10	0.14±0.9
Bulgaria	547	Jaeger MasterScreen	150	Body size adjusted	Jones–Meade	Largest	100	8.00	0.3±0.8
Bulgaria	335	Jaeger MasterScreen	150	Body size adjusted	Jones–Meade	Largest	100	10.20	NR
Mexico	191	Other	2240	Fixed	Jones–Meade	Average	100	14.10	0.04±1.2
Greece	942	Jaeger MasterScreen	460	Fixed	Unknown	Largest	100	27.60	0.3±0.9
New Zealand	151	SensorMedics Vmax Encore	10	Fixed	Jones–Meade	Average	100	4.60	−0.5±1.0
Italy	80	Other	100	Unknown	Unknown	Unknown	100	NR	0.06±0.9
Italy	3552	SensorMedics Vmax Encore	904	Unknown	Unknown	Average	100	25.70	0.2±1.0
Canada	541	Other	Various	Unknown	Unknown	Unknown	100	7.80	0.4±1.6

Data are presented as n or mean±sd, unless otherwise stated. V_D: dead space volume; FEV₁: forced expiratory volume in 1 s; NR: not reported.