Output of a spirometer<unk>  <unk>  is the maximum amount of air a person can inhale after a maximum exhalation. It is equal to the sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume. It is approximately equal to Forced<unk>  <unk> . A person's<unk>  can be measured by a wet or regular spirometer. In combination with other physiological measurements, the<unk>  can help make a diagnosis of underlying lung disease. Furthermore, the<unk>  is used to determine the severity of respiratory muscle involvement in neuromuscular disease, and can guide treatment decisions in Guillain–Barré syndrome and myasthenic crisis. A normal adult has a<unk>  between 3 and 5 litres. A human's<unk>  depends on age, sex, height, mass, and possibly ethnicity. However, the dependence on ethnicity is poorly understood or defined, as it was first established by studying black slaves in the 19th century and may be the result of conflation with environmental factors. Lung volumes and lung<unk> es refer to the volume of air associated with different phases of the respiratory cycle. Lung volumes are directly measured, whereas lung<unk> es are inferred from volumes.
Vital capacity
Functional residual capacity
Lung compliance
Peak expiratory flow
Ventilatory threshold
Integrated pulmonary index
Mandatory minute ventilation
Peak inspiratory pressure