Reference equations using segmented regression
| Estimate | SE | 95% CI | Adjusted R2 | RSE | |
| DLCO, females (n=530) (mL/min/mm Hg) Breakpoint=24.3 (95% CI 22.7 to 25.8) years old | |||||
| Intercept1 (for 5.0–24.2 years old) | −11.82 | 1.87 | -15.5 to 8.1 | 0.76 | 2.121 |
| Intercept2 (for 24.3–95.0 years old) | −1.54 | 3.132 | |||
| Age21 (for 5.0–24.2 years old) | 0.01534 | 0.00183 | 0.012 to 0.019 | ||
| Age22 (for 24.3–95.0 years old) | −0.0018 | 0.000081 | −0.002 to −0.002 | ||
| Height (cm) | 0.183 | 0.014 | 0.156 to 0.210 | ||
| Altitude (m) | 0.0041 | 0.0012 | 0.002 to 0.006 | ||
| DLCO, males (n=546) (mL/min/mm Hg) Breakpoint=22.7 (95% CI 21.2 to 24.0) years old | |||||
| Intercept1 (for 5.0–22.6 years old) | −15.22 | 2.3 | −19.7 to 10.7 | 0.80 | 2.621 |
| Intercept2 (for 22.7–95.0 years old) | 2.5 | 4.352 | |||
| Age21 (for 5.0–22.6 years) | 0.0323 | 0.0038 | 0.025 to 0.039 | ||
| Age22 (for 22.7–95.0 years old) | −0.00246 | 0.00011 | −0.009 to −0.008 | ||
| Height (cm) | 0.206 | 0.017 | 0.173 to 0.239 | ||
| Altitude (m) | 0.0041 | 0.0016 | 0.001 to 0.007 | ||
| DLNO, females (n=530) (mL/min/mm Hg) Breakpoint=22.6 (95% CI 20.6 to 24.5) years old | |||||
| Intercept1 (for 5.0–22.5 years old) | −66.43 | 8.4 | -82.9 to 50.0 | 0.79 | 8.601 |
| Intercept2 (for 22.6–95.0 years old) | −30.74 | 13.632 | |||
| Age21 (for 5.0–22.5 years old) | 0.0616 | 0.01 | 0.042 to 0.082 | ||
| Age22 (for 22.6–95.0 years old) | −0.00832 | 0.00034 | −0.028 to 0.011 | ||
| Height (cm) | 0.947 | 0.063 | 0.824 to 1.070 | ||
| PFT equipment | 15.17 | 1.31 | 12.6 to 17.7 | ||
| DLNO, males (n=546) (mL/min/mm Hg) Breakpoint=22.2 (95% CI 20.7 to 23.5) years old | |||||
| Intercept1 (for 5.0–22.1 years old) | −87.15 | 10.5 | -107.7 to 66.6 | 0.83 | 11.811 |
| Intercept2 (for 22.2–95.0 years old) | −14.02 | 19.252 | |||
| Age21 (for 5.0–22.1 years old) | 0.1375 | 0.018 | 0.103 to 0.173 | ||
| Age22 (for 22.2–95.0 years old) | −0.012 | 0.00048 | −0.013 to −0.011 | ||
| Height (cm) | 1.086 | 0.08 | 0.93 to 1.24 | ||
| PFT equipment | 18.00 | 1.83 | 14.4 to 21.6 | ||
| VA, females (n=530) (L) Breakpoint=30.3 (95% CI 28.0 to 32.4) years old | |||||
| Intercept1 (for 5.0–30.2 years old) | −4.16 | 0.32 | −4.8 to −3.5 | 0.80 | 0.391 |
| Intercept2 (for 30.3–95.0 years old) | −2.79 | 0.582 | |||
| Age21 (for 5.0–30.2 years old) | 0.00132 | 0.00017 | 0.001 to 0.002 | ||
| Age22 (for 30.3–95.0 years old) | −0.00018 | 0.00002 | −0.0002 to −0.0001 | ||
| Height (cm) | 0.05 | 0.0023 | 0.045 to 0.055 | ||
| PFT equipment | 0.2545 | 0.054 | 0.15 to 0.36 | ||
| VA males (n=546) (L). Breakpoint=27.0 (95% CI 25.1 to 28.8) years old | |||||
| Intercept1 (for 5.0–26.9 years old) | −5.64 | 0.36 | −6.4 to −4.9 | 0.86 | 0.461 |
| Intercept2 (for 27.0–95.0 years old) | −3.61 | 0.732 | |||
| Age21 (for 5.0–26.9 years old) | 0.00265 | 0.0003 | 0.002 to 0.003 | ||
| Age22 (for 27.0–95.0 years old) | −0.00013 | 0.00002 | −0.0003 to −0.0001 | ||
| Height (cm) | 0.060 | 0.0026 | 0.055 to 0.065 | ||
| PFT equipment | 0.241 | 0.07 | 0.11 to 0.37 | ||
For the PFT equipment, 1=Hyp’Air Compact, and 0=Jaeger Masterscreen. For example, for a man who is 26.9 years old with the same height and equipment used, the predicted alveolar volume (VA) (L)=0.0027‧(26.92)+0.06 ‧(180)+0.24–5.64=7.35 L with a lower limits of normal (LLN) of 7.35 – (0.46‧1.645)=6.59 L. For a man 27 years old, 180 cm tall, and who had the measurement performed on the Hyp’Air, the predicted VA (L) = –0.00013‧(272)+0.06‧(180)+0.24–3.61=7.34 L with the LLN=7.34 – (0.73‧1.645)=6.14 L.
DLCO, pulmonary diffusing capacity for carbon monoxide; DLNO, pulmonary diffusing capacity for nitric oxide; RSE, residual SE.