Final answer:
Normal spirometry numbers mean that the individual's lung function is healthy, without significant obstructions or restrictions. The FEV1/FVC ratio within expected ranges is key to diagnosing or ruling out various lung diseases.
Step-by-step explanation:
When spirometry numbers are normal, it suggests that the person tested has healthy lung function. An important metric in spirometry is the forceful expulsion of air from the lungs; specifically, the forced expiratory volume (FEV1) and the forced vital capacity (FVC). The FEV1/FVC ratio is crucial for diagnosing lung diseases, such as asthma, emphysema, and fibrosis.
In healthy individuals, this ratio is within expected ranges, indicating no significant obstruction or restriction in lung function. A high FEV1/FVC ratio may signal lung fibrosis, where the lung is stiff and noncompliant. Conversely, a low FEV1/FVC ratio could indicate obstructive diseases like asthma, where there is resistance to air flow out of the lungs.