Home Lung Function Test
How It Is Done
Before you begin to test your peak
expiratory flow (PEF), remove any gum or food you may have in your mouth.
Follow these steps to use your peak flow meter:
- Set the pointer on the gauge of the peak flow
meter to 0 (zero).
- Attach the mouthpiece to the peak flow
- Stand up or sit up straight to allow yourself to take a deep
breath. Whether you stand or sit up straight, make sure you use the same
position each time you test your PEF.
- Take a deep breath in. Place the peak flow meter
mouthpiece in your mouth and close your lips tightly around the outside of the
mouthpiece. Do not put your tongue inside the mouthpiece.
out as hard and as fast as you can using a huff. You do not need to breathe out
for more than a second.
- Note the value on the
- Move the pointer on the gauge back to 0 (zero) before you
- Blow into the peak flow meter 2 more times. Record your
values each time you blow. If you cough or make a mistake during the testing,
do the test over.
- After you have blown into your peak flow meter 3
times, record the highest value on your daily record sheet.
How It Feels
Breathing in and out very quickly during
these tests may make you feel lightheaded or may make you cough. If you feel
like you are going to pass out, stop the test.
There are no significant risks linked with
measuring peak expiratory flow (PEF). Breathing in and out very quickly during
the test may make you feel lightheaded or may make you cough. If you feel
lightheaded, stop the test.
A home lung function test uses a
peak flow meter or a home spirometer to monitor and evaluate any breathing problems you may have
on a day-to-day basis. A peak flow meter allows you to measure your
peak expiratory flow (PEF). PEF measures how fast you
can exhale using the greatest effort. A home spirometer allows you to measure your forced expiratory volume at 1 second (FEV1). Results from these tests can be compared to
monitor the progression of disease or help measure your response to medical
treatment for a long-term (chronic) lung disease, such as
Peak flows are compared to charts
that list normal values based on age, sex, race, and height. They also can be
compared with your personal best measurement. Check with your doctor or read
the information included with your peak flow meter to find your normal range,
which will vary depending on the type of breathing problems you may have. If
you find abnormal results on any of the tests, discuss them with your
- Normally, peak flows vary slightly throughout the day. They are
usually lower in the morning and higher in the afternoon.
- A person with poorly controlled asthma may have peak flows that
vary more widely throughout the day.