Summary of the practical recommendations for applying Global Lung Function Initiative transfer factor of the lung for carbon monoxide (TLCO) reference values

Barometric pressure (altitude)TLCO and KCO values should be adjusted to standard pressure (101.3 kPa or 760 mmHg) prior to calculation of predicted values
Anatomic dead spaceAnatomic dead space should be either measured from the tracer gas washout or estimated using body size
HbTLCO values should be uncorrected for Hb; Hb levels should be considered in the interpretation

Hb: haemoglobin; KCO: transfer coefficient of the lung for carbon monoxide.