Reduced vital capacity SNOMEDCT_US:607007 Decreased vital capacity An abnormal reduction on the vital capacity, which is defined as the total lung capacity (volume of air in the lungs at maximal inflation) less the residual volume (i.e., volume of air in the lungs following maximal exhalation) of the lung. SNOMEDCT_US:274715008 UMLS:C0520831 UMLS:C0476408 HP:0002792 Abnormality on pulmonary function testing