1. What is FEV1/FVC Ratio?

The FEV1/FVC ratio is a measurement used in pulmonary function tests to assess lung function. It represents the proportion of a person's vital capacity that they are able to expire in the first second of forced expiration.

2. How Does the Calculator Work?

The calculator uses the simple ratio formula:

Where:

• \( FEV1 \) — Forced Expiratory Volume in 1 second (L)
• \( FVC \) — Forced Vital Capacity (L)

Explanation: The ratio compares the amount of air exhaled in the first second to the total amount of air that can be forcibly exhaled.

3. Importance of FEV1/FVC Ratio

Details: This ratio is crucial for diagnosing obstructive lung diseases like asthma and COPD. A reduced ratio indicates airway obstruction, while a normal or increased ratio suggests restrictive lung disease.

4. Using the Calculator

Tips: Enter FEV1 and FVC values in liters. Both values must be positive numbers obtained from spirometry testing.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal FEV1/FVC ratio?
A: A normal ratio is typically above 0.70-0.75 in adults, though it varies with age, gender, and ethnicity.

Q2: What does a low FEV1/FVC ratio indicate?
A: A ratio below 0.70 suggests obstructive lung disease, where airflow is limited during exhalation.

Q3: What does a normal or high ratio with low FVC indicate?
A: This pattern suggests restrictive lung disease, where lung expansion is limited.

Q4: How is spirometry testing performed?
A: The patient takes a deep breath and exhales as forcefully and completely as possible into a spirometer.

Q5: Are there any limitations to this measurement?
A: The test requires good patient effort and cooperation. Results should be interpreted by a healthcare professional in clinical context.