The computer graded the QFVC=F and the QFEV1=A. The computer FVC grade was F because the FVC repeatability was 480 ml, much greater than the 150 ml repeatability criteria. The lack of a repeatable FVC is due to an abrupt termination in the volume-time curve, perhaps cause by glottis closure. Abrupt termination is suggested as the subject is 51 years old and there is little variation in the volume once the abrupt termination occurs. The last curve (#4 orange) is a good curve with a good plateau. Since curves #1 (black) and curve #2 (green) have very similar shapes and similar FEV1's to those of the last curve (orange), there is reason to expect the FVC's represent the subject maximal effort FVC's. The FEV1's are not affected by the abrupt termination since it abrupt termination occurs after the first second of exhalation. The revised grades of QFVC=C and QFEV1=A.
