Summary of the considerations for diffusing capacity for carbon monoxide(DL,CO) interpretation
| Refer to a scheme to grade the severity of reductions in DL,CO (table 14) |
| Interpreting DL,CO in conjunction with spirometry and lung volumes may assist in diagnosing the underlying disease (fig. 2) |
| Adjustments of DL,CO for changes in haemoglobin and carboxyhaemoglobin are important |
| The relationship between DL,CO and lung volume is not linear, so DL,CO/VA or DL,CO/TLC do not provide an appropriate way to normalise DL,CO for lung volume |
| Nonlinear adjustments may be considered, but their clinical utility must be established before they can be recommended |
VA: alveolar volume; TLC: total lung capacity.