What are the FEV1 and FEV1/FVC values that define normal lung function?

The correct choice indicates that normal lung function is characterized by an FEV1 (Forced Expiratory Volume in one second) value of 80% or greater of the predicted value, along with an FEV1/FVC (Forced Vital Capacity) ratio of 85% or higher. These thresholds are widely accepted in pulmonary medicine as indicators of effective lung function without significant obstruction.

When evaluating lung function, the FEV1 value reflects how much air a person can forcibly exhale in one second, whereas the FEV1/FVC ratio compares the volume of air exhaled in the first second to the total volume of air exhaled. The established normal ranges are based on population studies and adjustments made for age, sex, height, and ethnicity. An FEV1 of 80% along with an FEV1/FVC ratio of 85% serves as a guideline for clinicians when assessing respiratory health, supporting the diagnosis of normal lung function in individuals without any obstructive or restrictive lung diseases.

This option aligns with the standard definitions used in clinical practice, allowing healthcare professionals to determine whether further evaluation or treatment for conditions like asthma or COPD is necessary.