Elevated RV/TLC ratio 2020-11-24T10:58:46Z Hyperinflation on pulmonary function test An increase in the ratio of residual volume (RV) to total lung capacity (TLC) on pulmonary function testing. RV is the amount of air remaining aftermaximal expiration and TLC is the total amount of air in theungs at full inspiration. These volumes cannot be determined by spirometry, but can be measured by inert gas dilution, nitrogen washout, and (3) body plethysmography. An elevated RV/TLC can be interpreted as a sign of air trapping and hyperinflation. Overinflation on pulmonary function test Abnormal RV/TLC ratio