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))

MSL
Male
 TLCO mmol·min−1·kPa−1
DLCO mL·min−1·mmHg−1
exp(−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−1
exp(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 Lexp(−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−1
exp(−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−1
exp(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 Lexp(−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.