What Are Lung Function Tests?
Lung function tests measure the size of your lungs,
how much air you can breathe in and out, how fast you can breathe air out, and
how well your lungs deliver oxygen to your blood. These tests also are called
pulmonary (PULL-mun-ary) function tests.
Lung function tests are used to look for the cause
of breathing problems (like shortness of breath). These tests are used to check
for conditions such as
asthma,
lung
tissue scarring,
sarcoidosis
(sar-koy-DO-sis), and
COPD
(chronic obstructive pulmonary disease).
Lung function tests also are used to see how well
treatments for breathing problems, such as asthma medicines, are working. The
tests may be used to check on whether a condition, such lung tissue scarring,
is getting worse.
Overview
Lung function tests measure:
- How much air you can take into your lungs. This
amount is compared to that of other people your age, height, and sex. This
allows your doctor to see whether you're in the normal range.
- How much air you can blow out of your lungs and
how fast you can do it.
- How well your lungs deliver oxygen to your blood.
- How strong your breathing muscles are.
Breathing Tests
The breathing tests most often used are:
- Spirometry (spi-ROM-eh-tre). This test measures
how much air you can breathe in and out. It also measures how fast you can blow
air out.
- Peak flow meter. This meter is a small, hand-held
device thats sometimes used by people who have asthma. The meter helps
track their breathing.
- Lung volume measurement. This test, in addition
to spirometry, measures how much air you have left in your lungs after you
breathe out completely.
- Lung diffusing capacity. This test measures how
well oxygen passes from your lungs to your bloodstream.
These tests may not show whats causing
breathing problems. Other tests, such as a cardiopulmonary exercise test, also
may be done. This test measures how well your lungs and heart work while you
exercise on a treadmill or bicycle.
Tests To Measure Oxygen Level
Pulse oximetry and arterial blood gas are two tests
used to measure the oxygen level in the blood. They're also called blood oxygen
tests.
Pulse oximetry measures blood oxygen levels using a
special light. During an arterial blood gas test, your doctor inserts a small
needle into an artery, usually in your wrist, and takes a sample of blood. The
oxygen level of the blood sample is then checked.
Outlook
Lung function tests usually are painless and rarely
cause side effects. You may feel some discomfort during the arterial blood gas
test when the needle is inserted into the artery.
(For more information on healthy lung function, see
the Diseases and Conditions Index "How the Lungs Work" article.)
February 2008 |