Certified Pulmonary Function Technologist (CPFT) Practice Exam

What is a common indicator of obstructive lung disease in spirometry results?

1. Increased FVC

2. Decreased FEV1 and FEV1/FVC ratio

3. Increased MVV

4. Decreased lung volumes

The correct answer is: Decreased FEV1 and FEV1/FVC ratio

In spirometry, obstructive lung disease is characterized by difficulty exhaling air due to airway obstruction. A common indicator of this condition is the presence of decreased Forced Expiratory Volume in one second (FEV1) along with a decreased FEV1/FVC (Forced Vital Capacity) ratio. In patients with obstructive lung diseases such as asthma and chronic obstructive pulmonary disease (COPD), the FEV1 is significantly reduced because the airflow is limited during the initial part of the exhalation. As a result, the FEV1/FVC ratio is also decreased, typically below the normal threshold of 70%. This combination indicates that the amount of air forcibly exhaled in the first second is insufficient relative to the total volume exhaled, signifying airflow obstruction. The other choices do not typically correlate with obstructive lung disease. Increased FVC would not align with obstructive patterns, while increased Maximum Voluntary Ventilation (MVV) is often seen in restrictive lung disease rather than obstructive patterns. Decreased lung volumes can occur in various diseases but are not specific indicators of obstruction. Thus, the correct choice highlights the hallmark features associated with obstructive lung disease in spirometry diagnostics.