Estimating FVC From FEV2 and FEV3: Assessment of a Surrogate Spirometric Parameter.

The article proposes a regression equation for estimating FVC from measured values of the forced expiratory volume in 2 s and forced expiratory volume in 3 s. In the context that spirometry is essential in assessing respiratory disorders, FVC is an important measurement to diagnose the presence of obstructive lung disease and to evaluate restrictive disease. The main findings of this study are that FEV3 can be used to estimate FVC with reasonable accuracy. Although this surrogate parameter confers benefits for interpreting spirometry results when spirometric end-of-test criteria are not satisfied, estimates of the true FVC are imperfect and use of the FEV1 estimated FVC3 does not eliminate the risk of misclassifying the presence of obstruction.