THE GROWING interest in chronic respiratory disease has led to an increasing use of simple ventilatory tests. Large numbers of presumably normal persons have been tested in many community pulmonary surveys, and ventilatory testing of one sort or another will increasingly become a part of routine medical examinations. This growing interest in a major health problem is commendable. However, the use of simple ventilatory tests on asymptomatic subjects has implications which must be distinguished from the sophisticated testing on pulmonary cripples which characterizes a physiological profile in a pulmonary laboratory.
The state of the art of simple spirometry is in some respects analagous to the earlier days of electrocardiography. At that time the ranges of normal were less well-known than they are today, and doubtless large numbers of people without heart disease were done a disservice by their physician by virtue of an ECG of uncertain significance. The analogy between