Figures
- FIGURE 1
a) Predicted transfer factor of the lung for carbon monoxide (TLCO) in i) males n=4859 and ii) females n=4851; b) alveolar volume (VA) (at standard temperature, pressure and dry conditions) in i) males n=4793 and ii) females n=4837; and c) transfer coefficient of the lung for carbon monoxide (KCO) in i) males n=4793 and ii) females n=4837. Data are presented as the predicted values for age (assuming an average height at each) and 95% confidence limits. Prediction equations are overlaid on observed values. The average height used in children was the 50th height-for-age centile from Centers for Disease Control and Prevention growth charts [4], whereas in adults, the average height observed in the study population was used (172 cm in males and 162 cm in females).
- FIGURE 2
Between-subject variability of transfer factor of the lung for carbon monoxide (TLCO) across age; the variability of forced expiratory volume in 1 s (FEV1) in males and females is included as a comparator.
- FIGURE 3
Differences in a) transfer factor of the lung for carbon monoxide (TLCO) in i) males n=4859 and ii) females n=4851; b) alveolar volume (VA) in i) males n=4793 and ii) females n=4837; and c) transfer coefficient of the lung for carbon monoxide (KCO) z-scores in i) males n=4793 and ii) females n=4837 according to equipment in Caucasian subjects. Boxplots indicate the median value (centre line); interquartile range (box) and minimum and maximum values, excluding outliers greater than three times the lower quartile (error bars).
- FIGURE 4
Comparison of transfer factor of the lung for carbon monoxide (TLCO) reference equations to the current Global Lung Function Initiative (GLI) equations. Equations found in a) most commercially available equipment and b) more recently published studies.
Tables
- 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 VD 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. VD: dead space volume; FEV1: forced expiratory volume in 1 s; NR: not reported.
- TABLE 2
Summary of equations for predicted values for the median (M), the variability around the median (S) and the skewness (L) for each of the transfer factor of the lung for carbon monoxide (TLCO) test outcomes (TLCO, transfer coefficient of the lung for carbon monoxide (KCO) and alveolar volume (VA))
M S L Male TLCO mmol·min−1·kPa−1
DLCO mL·min−1·mmHg−1exp(−8.758548+2.151173·ln(height)−0.027927·ln(age)+Mspline) exp(−7.664278+2.151173·ln(height)−0.027927·ln(age)+Mspline) exp(−1.98249+0.03430·ln(age)+Sspline) 0.38713 KCO (SI) mmol·min−1·kPa−1·L−1
KCO (trad) mL·min−1·mmHg−1·L−1exp(2.47708−0.30924·ln(height)−0.12173·ln(age)+Mspline) exp(3.57135−0.30924·ln(height)−0.12173·ln(age)+Mspline) exp(−1.97633+0.01536·ln(age)+Sspline) 0.64731 VA L exp(−11.175544+2.450697·ln(height)+0.092353·ln(age)+Mspline) exp(−2.24731+0.03069·ln(age)+Sspline) 0.69230 Female TLCO mmol·min−1·kPa−1
DLCO mL·min−1·mmHg−1exp(−9.008743+2.171106·ln(height)−0.025634·ln(age)+Mspline) exp(−7.914474+2.171106·ln(height)−0.025634·ln(age)+Mspline) exp(−1.84162+0.01379·ln(age)+Sspline) −0.27064 KCO (SI) mmol·min−1·kPa−1·L−1
KCO (trad) mL·min−1·mmHg−1·L−1exp(3.009809−0.437869·ln(height)−0.102958·ln(age)+Mspline) exp(4.104078−0.437869·ln(height)−0.102958·ln(age)+Mspline) exp(−1.63864−0.07180·ln(age)+Sspline) 0.41767 VA L exp(−12.205809+2.649906·ln(height)+0.074487·ln(age)+Mspline) exp(−2.11477+0.01328·ln(age)+Sspline) 0.11093 Height and age are expressed as cm and years, respectively. Lower limit of normal (5th percentile): exp(ln(M)+ln(1−1.645·L·S)/L); upper limit of normal (5th percentile): exp(ln(M)+ln(1+1.645·L·S)/L); z-score: ((measured/M)L-1)/(L·S); % predicted: (measured/M)·100; exp(): natural exponential; ln(): natural logarithm. Mspline and Sspline correspond to the age-varying coefficients provided in the online supplementary material.
- TABLE 3
Comparison of predicted values for individuals using available transfer factor of the lung for carbon monoxide (TLCO) reference values
First author, year [reference] TLCO mmol·min−1·kPa−1 178-cm, 64-year-old male 178-cm, 20-year-old male 150-cm, 10-year-old male GLI, 2017 9.2 10.9 6.4 Crapo, 1981 [16] 11.3 14.5 Miller, 1983 [19] 9.2 12.6 Roca, 1990 [17] 10.3 13.3 Gutierrez, 2004 [28] 8.3 10.5 Thompson, 2008 [26] 9.3 10.8 Koopman, 2011 [22] 6.4 Kim, 2012 [23] 6.0 The list of equations is not meant to be comprehensive, rather it provides a range of differences that might be expected. GLI: Global Lung Function Initiative.
- TABLE 4
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 space Anatomic dead space should be either measured from the tracer gas washout or estimated using body size Hb TLCO 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.
Supplementary Material
Please note: supplementary material is not edited by the Editorial Office, and is uploaded as it has been supplied by the author.
Supplementary material ERJ-00010-2017_Supplement
Lookup table (S.I. units) ERJ-00010-2017_Lookup_Table_SI_Units
Lookup table (traditional units) ERJ-00010-2017_Lookup_Table_Traditional_Units
TLCO calculator ERJ-00010-2017_TLCO_Calculator
TLCO calculator help document ERJ-00010-2017_TLCO_Calculator_Help
