The flow volume curve: normal standards in young subjects.

During epidemiological survey, satisfactory flow-volume data were obtained from 438 young Italian Boy-Scouts. Data from 302 non-smoking subjects (170 males and 132 females, ranging in age from 10 to 20 years) free of symptoms or history of cardiorespiratory disease were used in determining "normal" prediction equations and nomograms for peak expiratory flow (PEF), maximal expiratory flow at 75 percent (V 75%), 50 percent (V 50%), 25 percent (V 25%) of the forced vital capacity. The flow-volume curve showed for the same height and age evident intersubject variability. The prediction equations and nomograms give mean values but no information on scatter.