Measurement of lung volumes.

Measurements of lung volume play an integral role in the laboratory evaluation of patients with known or suspected lung disease. Several techniques are available to measure absolute lung volumes (containing residual volume). It should be noted that these techniques measure different theoretical volumes and may produce different results in patients with lung disease. Lung volume measurements are typically elevated in obstructive diseases and reduced in restrictive diseases, making them useful tests in diagnosing and distinguishing these two general classes of disease.