Table 1. Selection of spirometry test values.

Score	Adequate number of curves		Reproducibility gap* between two largest values
A	3	and	<100 mL
B	3	and	<150 mL
C	2	and	<250 mL
D	1
F	0

A and B are possible to interpret; C and D are possible to interpret with caution; F is impossible to interpret. When determined as “possible to interpret,” the values of FEV₁ and FVC are adopted from the largest values. Each values of FVC and FEV₁ may be obtained at different curves.

^*Gap between the largest value minus the second largest value.

FVC: forced vital capacity; FEV₁: forced expiratory volume at 1 second.