PEFR Medical Abbreviation

PEFR stands for Peak Expiratory Flow Rate — a key respiratory measurement that shows how much air a person can forcefully blow out of their lungs in one quick breath. It’s sometimes referred to as Peak Expiratory Flow (PEF).

What Does PEFR Measure?

PEFR measures the speed of exhaled air in litres per minute (L/min) after a full inhalation. In simple terms, it tells us how quickly air can move out of the lungs — a useful indicator of lung function.

This test is most commonly used by people with asthma or other chronic lung conditions to monitor changes in airflow.

Why Is PEFR Important?

A person’s peak expiratory flow reflects how open their airways are. It helps in identifying:

• If a person has asthma

• Whether their asthma is under control

• If they are having an asthma attack

Common Uses of PEFR

Doctors and patients use Peak Expiratory Flow Rate to:

• Monitor asthma symptoms

• Track chronic lung disease progression

• Assess how well treatments or inhalers are working

• Detect early signs of flare-ups or airway narrowing

How Is Peak Expiratory Flow Rate Measured

PEFR is measured using a small handheld device called a peak flow meter. Here’s how the test is usually performed:

1. Set the dial to zero

2. Take a deep breath to fill your lungs completely

3. Place your mouth firmly around the mouthpiece

4. Blow out as hard and fast as you can in one go

5. Record the number the dial reaches

6. Repeat three times and use the highest reading

How to Interpret PEFR Results

Results are compared to reference values based on age, sex, height, and sometimes weight. These values help define what’s normal for each individual.

• 80–100% of predicted value: Normal or well-controlled

• 50–79%: Moderate airflow limitation — may need treatment adjustment

• Below 50%: Medical emergency — could indicate severe airway narrowing

Peak Expiratory Flow Rate Summary

• PEFR = Peak Expiratory Flow Rate

• Measured in L/min

• Used to monitor asthma and lung health

• A drop in PEFR could signal a flare-up or airway problem

• Always compare results to personal best or reference values