Lung function

Alternative names:

pulmonary function

How the test is performed:

There are 6 lung function tests that can be done at home.
Match Test: Light a match and hold it 6 inches from your mouth. Take a deep breath, then with your mouth open, try to blow out the match with a forceful exhalation. Do not pucker your lips to increase the force of the air flow. This checks the force of the exhalation (breathing out).

Forced expiratory time (FET): Breathe in as deeply as possible. With your mouth open, exhale as fast and completely as possible. Use a watch to time the number of seconds it takes for you to exhale the air. Repeat this 3 times and record the fastest time.

Peak expiratory flow rate (PEFR): This test requires a peak expiratory flow monitor. 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.

Forced vital capacity (FVC) and forced expiratory volume in one second (FEV): This test requires a hand-held spirometer. Breathe in as deeply as possible, then blow out into the mouthpiece of the instrument as fast, hard, and long as possible. Expel all of the air in your lungs. Repeat it 3 times and record the highest numbers.

Maximum ventilatory volume (MVV): This test requires a spirometer. Blow as hard and fast as possible into the mouthpiece with repeated rapid in and out breaths for exactly 15 seconds. Multiply the recorded number by 4 to determine the value for 1 minute.

How to prepare for the test:

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

Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:

• infant test or procedure preparation (birth to 1 year)
• toddler test or procedure preparation (1 to 3 years)
• preschooler test or procedure preparation (3 to 6 years)
• schoolage test or procedure preparation (6 to 12 years)
• adolescent test or procedure preparation (12 to 18 years)

How the test will feel:

There is usually no discomfort.

Why the test is performed:

Home testing may be useful in monitoring the progress of a disease such as asthma, emphysema, or chronic bronchitis. It can assess the effectiveness of various treatments. It is a way to screen for some lung diseases. An improvement in lung function can be measured if one is starting an exercise program or has stopped smoking.