Based on spirometry results with FEV1= 4.2L and FVC= 5.1L, what is the diagnosis?

The key to understanding this scenario lies in the values of FEV1 (forced expiratory volume in one second) and FVC (forced vital capacity). In this case, the FEV1 is 4.2L and the FVC is 5.1L. To assess lung function, the FEV1/FVC ratio is calculated. In healthy individuals, this ratio typically exceeds 70% (or 0.7).

The FEV1/FVC ratio can be computed as follows:

FEV1/FVC = 4.2L / 5.1L = 0.82 (or 82%)

This ratio indicates that both the FEV1 and FVC are within normal limits, as neither value indicates a significant obstruction nor restriction. A normal ratio suggests no obstructive lung disease (where FEV1 would be reduced relative to FVC) or restrictive lung disease (where both FEV1 and FVC would be reduced but FEV1/FVC may be normal or increased).

Therefore, this data supports the conclusion that the individual exhibits normal pulmonary function tests. The absence of any significant abnormalities in the FEV1, FVC, and the FEV1/FVC ratio indicates that there are no