Last Updated on January 6, 2025 by Analgesia team
PEFR Medical Abbreviation
PEFR is a medical abbreviation for peak expiratory flow rate, which measures how much air a person can forcefully exhale in one breath:
It’s also known as peak expiratory flow (PEF).
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What it measures
The volume of air a person can exhale in liters per minute (L/min) after a full inhalation. That is, it is a quick test to measure air flow out of the lungs. Peak flow measurement is mostly done by people with asthma or a long-term (chronic) lung disease.
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What it indicates
How open a person’s airways are, and how well their lungs are ventilating. PEFR indicates if someone has asthma, if their asthma is well controlled, or if they’re having an asthma attack.
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How it’s used
To monitor asthma and other chronic lung conditions, and to assess the effectiveness of treatments
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How it’s measured
Using a handheld peak flow meter, which involves breathing out into the mouthpiece while the dial is set to zero.
- Fill your lungs completely with a deep breath
- Put your mouth around the mouthpiece and close your lips tightly
- Blow out all the air as hard and fast as you can in one breath
- Write down the number on the meter by the marker
- Repeat three times
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How to interpret resultsCompare the measurement to reference values based on the patient’s age, sex, height, weight, and other factors. A PEFR that’s less than 50% of a person’s normal value is a medical alert, and indicates severe airway narrowing.