The computer grades are QFVC=C, QFEV1=A. The lower computer FVC grade is due to a lack of a repeatable FVC (closest FVC is 155 ml). Curve #4 (orange) is larger than the other curves possibly due to a better inhalation. However, the FEV1/FVC%=54.8% which is low. So, the larger values may be due the clearance of mucous with successive maneuvers or a deeper breath. Because of the similarity between the curves and the lower ratio, the FVC grade is increased to a B or QFVC=B and QFEV1 remains an A. There is less disagreement with this test but it illustrates the fact that older subjects often require longer to reach a plateau. So, if too strict of an end of test criterion is used, the result may be an exclusion of a disproportionate number of older subjects.
