Lung function test is basically performed for the diagnosis of asthma. These tests measure the size of the lungs, the volume of air inhaled and exhaled as well as how well the lungs deliver oxygen to the blood. These tests are also known by the name of pulmonary function tests.

These tests help in finding out the cause of breathing problems as well as for the diagnosis of respiratory problems like lung tissue scarring, sarcoidosis and COPD (chronic obstructive pulmonary disease) apart from asthma.

These tests also detect how well treatments for asthma are working. After a lung function test is conducted, the reports are compared to that of the other people with same age, height and sex. Thus the doctor checks out if the patient lies in the normal range. It is also measured as to how much air one can blow out of the lungs and how fast. These tests also detect how well the lungs deliver oxygen to the blood. They also detect how strong the breathing muscles are.

This is one of the most important tests performed for the diagnosis of asthma by the doctors. You can also get a lot of information online.