Inspired gas mixtures used during measurements of normal carbon monoxide(CO) uptake for commonly used reference equations
| Author [Ref.] | Gas mixture# |
| Teculescu 75 | 1.5% He, balance air (FI,O2 0.20) |
| Van Ganse 76 | 14–15% He, balance air (FI,O2 0.18) |
| Frans 77 | 10% He, 18% O2 |
| Crapo 78 | 10% He, 25% O2 (comparable to 21% at sea level) |
| Paoletti 79 | 10% He, 20% O2 |
| Knudson 80 | 10% He, 21% O2 |
| Roca 81 | 13% He, 18% O2 |
| Huang 25 | 0.3% CH4, 0.3% C2H2, balance air (FI,O2 0.20) |
| Miller 82 | 10% He, ?balance air |
He: helium; FI,O2: inspired oxygen fraction; CH4: methane; C2H2: acetylene. #: in addition to 0.3% CO.