When is FRC measured?

Functional residual capacity (FRC) is the amount of air that remains in your lungs after a normal and passive exhalation. This air is the only source of oxygen and carbon dioxide exchange between your lungs and blood when you exhale. Doctors use FRC and a variety of other lung function tests to screen for respiratory diseases.

Why is FRC important?

They will protect you in the most effective way from risks and potential dangerous elements, but they do not take those risks away. FRC provides valuable time to manage the situation, stop the spread, and give you time to think and act quickly before the injury becomes more serious.

What is FRC in spirometry?

FRC is the sum of expiratory reserve volume (ERV) and residual volume (RV) and measures approximately 3000 mL in a 70 kg, average-sized male. It cannot be estimated through spirometry, since it includes the residual volume.

What does a low FRC mean?

A lowered or elevated FRC is often an indication of some form of respiratory disease. In restrictive diseases, the decreased total lung capacity leads to a lower FRC. In turn in obstructive diseases, the FRC is increased.