Lung function test, girl breathing into peak flow meter (spirometer) - stock photo

Lung fucntion test. Six year old girl breathing into a peak flow meter (spirometer). A peak flow meter is used to monitor lung function by measuring the maximum rate at which air is expelled from the lungs. The patient takes a deep breath and breathes out as hard as possible into the mouthpiece. This test can be used to detect asthma and other lung disorders.