The computer grades are QFVC=A, QFEV1=F. The low computer FEV1 grade is due to a lack of a repeatable FEV1 (closest FEV1 is 430 ml). Curve #4 (red) is unacceptable due to a cough. However, the shape of the flow-volume curves, and particularly curve #1 (black) indicate that a maximal effort or flow limitation was likely achieved for the first curve (black). So although the FEV1 is not repeatable, it is unlikely that a better effort would produce a higher FEV1. Thus FEV1 grade is increased to a C to reflect this fact. The FVC grade is lowered to a B or C as there are only two acceptable curves -- QFVC=C and QFEV1=C.
