Spirometric standards for healthy black adults

Forced expiratory spirometric studies were performed on 512 nonsmoking black adult men and women with negative cardiorespiratory histories. Regression equations were calculated for forced vital capacity (FVC), percent vital capacity in 1 second (% FEV(1)), and forced midexpiratory flow rate FEF(25-75)%), using height and age. These equations resulted in predicted values 3.5 to 23 percent lower than commonly used standards. The wide range of variation means that a single correction factor is inadequate when considering ethnic differences. In contrast, FEV(1)/FVC was within the accepted range of normal for all ethnic groups. In the 30 percent of subjects in whom sitting height was measured, it was not significantly different from one half the standing height; thus, sitting height is also an inadequate correction factor. Tables of predicted values were constructed for easy reference, with the hope that use of racespecific standards for pulmonary function testing will become widespread.