The computer graded this tests as QFVC=F and QFEV1=C. Curve #1 (red) is rejected because of a large extrapolated volume. The computer grades for FVC and FEV1 are based on the repeatability of the FVC and FEV1. Although this is supposed to be a "normal" subject, with a ratio of 63.7%, this elderly subject (76 years old) probably has airways obstruction -- notice it takes the subject 20-seconds to reach a plateau. So, the lack of a repeatable test, is likely due to the airways obstruction and not a lack of effort. Therefore there is reason to expect that the FVC's represent the subject's maximal effort -- thus the revised grades of QFVC=C and QFEV1=A.
