Peak expiratory flow rate

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Lungs

Match test

Spirometry

The peak expiratory flow rate measures how fast a person can breath out (exhale) air. It is one of many tests that measure the how well your airways work.

Peak flow

This test requires a peak expiratory flow monitor, a small hand-held device with a mouthpiece at one end and a scale with a moveable indicator (usually a small plastic arrow).

• Breathe in as deeply as possible.
• Blow into the instrument's mouthpiece as hard and fast as possible.
• Do this 3 times, and record the highest flow rate.

Loosen any tight clothing that might restrict your breathing. Sit up straight or stand while performing the tests.

There is usually no discomfort. Rarely, repeated efforts may cause some lightheadedness.

The test is commonly used to diagnose and monitor lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), emphysema, or chronic bronchitis. Home monitoring can be used to determine if treatments are working or detect when a condition is getting worse.  

Review Date: 02/27/2006
Reviewed By: David A. Kaufman, M.D., Assistant Professor, Division of Pulmonary, Critical Care & Sleep Medicine, Mount Sinai School of Medicine, New York, NY. Review provided by VeriMed Healthcare Network.