Certified Pulmonary Function Technologist (CPFT) Practice Exam

The normal FEV1 (Forced Expiratory Volume in one second) percentage typically refers to the ratio of the FEV1 to the forced vital capacity (FVC) expressed as a percentage, which is a key metric in assessing lung function, particularly in diagnosing obstructive and restrictive airway diseases. In healthy individuals, the FEV1/FVC ratio is generally expected to be around 80%, indicating that approximately 80% of the total volume of air can be forcibly expelled in the first second of a maximal expiration. This percentage is considered a benchmark for normal respiratory function in adults, reflecting efficient lung mechanics. Therefore, recognizing that 80% is the threshold that defines normal function is crucial in evaluating and interpreting pulmonary function tests. Other values like 60%, 70%, or 90% represent deviations from the norm and could indicate varying degrees of obstruction or restriction in lung function, thus they are not considered normal.