The computer grades are QFVC=F and QFEV1=A. The exhalation is longer than 6-seconds for all curves; however, none of the curves have a plateau in the volume-time curve. The computer grades for FVC are F as no curves have a satisfactory end of test, and for FEV1 are A as the FEV1 is not affected by the early termination. Notice that the difference between the FVC for the orange curve #4 (4.82 L ending at 9-seconds) is 200 ml less than the maximum curve (5.02 L) which stops at 13 seconds (black curve #1). Assuming the flow was constant after 9 seconds, the amount of volume added by going to 15 seconds on the largest curve would be 100 ml, thus the FVC's are valid (within 150 ml) even with no plateaus in the volume-time curves. Also given the repeatability of the volume-time curves, there is reason to expect that the other curves with early termination would reach about the same FVC's as the black curve #1 and green curve #2 had the exhalation continued -- thus the revised grades of QFVC=B and QFEV1=A.
