<prompt> Answer this question truthfullyWhat is the name of the lung volume that cannot be measured using spirometry?  <response>: <reason> The lung volume that cannot be measured using spirometry is called the residual volume. The residual volume is the amount of air that remains in the lungs after a maximal exhalation. This volume cannot be measured using spirometry, which is a pulmonary function test that measures the amount of air that can be forcefully exhaled after a maximal inhalation. The residual volume can be measured using other techniques, such as body plethysmography or gas dilution. 