1. What is Peak Flow Test?

The Peak Flow Test measures how fast a person can exhale air from their lungs. It's commonly used to monitor and manage asthma and other respiratory conditions by measuring Peak Expiratory Flow (PEF).

2. How Does the Calculator Work?

The calculator uses the PEF percentage formula:

Where:

• \( Measured \) — Actual measured peak flow value (L/min)
• \( Predicted \) — Predicted normal peak flow value (L/min)
• \( PEF \) — Peak Expiratory Flow percentage (%)

Explanation: The formula calculates what percentage of the predicted normal value the measured value represents, helping assess lung function.

3. Importance of PEF Calculation

Details: PEF monitoring helps track asthma control, detect early signs of worsening, guide treatment decisions, and assess response to medications.

4. Using the Calculator

Tips: Enter both measured and predicted peak flow values in liters per minute (L/min). Values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal PEF percentage?
A: Generally, 80-100% of predicted is considered normal. Below 80% may indicate airway obstruction.

Q2: How are predicted values determined?
A: Predicted values are based on age, height, gender, and ethnicity using standardized reference equations.

Q3: When should peak flow be measured?
A: Best measured in the morning and evening, before taking asthma medications, and when symptoms occur.

Q4: What affects peak flow readings?
A: Technique, time of day, recent medication use, respiratory infections, and environmental factors can affect readings.

Q5: How often should peak flow be monitored?
A: Frequency depends on asthma severity - daily for moderate to severe asthma, or as recommended by healthcare provider.