Which of the subsequent lung volumes or capacities cannot be accurately determined using spirometry, a technique commonly employed in pulmonary function testing?
Functional residual capacity (FRC)
Residual volume (RV)
Total lung capacity (TLC)
Vital capacity (VC)
Spirometry is a technique used to measure lung volumes and capacities, but it is not capable of directly measuring the residual volume (RV). The residual volume is the amount of air that remains in the lungs after maximal exhalation, and it cannot be measured accurately using spirometry alone. Hence, the correct answer is option 2.