Normal predicted values of single-breath diffusing capacity of the lung in healthy nonsmoking adults.

Prediction equations for the carbon monoxide diffusing capacity of the lung (DLCO) and diffusing capacity per liter of lung volume (DLCO/VA) were derived from 90 normal nonsmoking subjects (40 men and 50 women), using a standardized single-breath technique for determining carbon monoxide diffusing capacity. The results obtained are as follows: 1. The mean values for DLCO and DLCO/VA were 28.05±5.07 ml/min/mmHg, 4.569±0.694 ml/min/mmHg/L for men and 20.79±4.03 ml/min/mmHg, 4.695±0.743 ml/min/mmHg/L for women, respectively. 2. The values for DLCO and DLCO/VA disclosed significantly negative correlation with advancing age and positive correlation with height. 3. Normal prediction formulas were obtained for diffusing capacity, using age and height.