Why do I need a pulmonary functioning test after starting my medication?

As you know, asthma is a disease characterized by both hyperactive smooth muscles in the small airways of the lungs as well as a process of airway inflammation. Fortunately, there are a number of types of medications that can be used to treat the symptoms of asthma, including bronchodilators (such as albuterol) and anti-inflammatory inhaled steroids (such as fluticasone) among others. Pulmonary function testing can be very helpful in determining the severity of diseases affecting the lungs. The tests can provide detail in the measurement of the lung volumes, degree of obstruction or restriction of the airways caused by the disease process, and quantify the response to the use of new medications. Your doctor is asking for pulmonary function testing to see if there is a residual deficit in your lung function even after the initiation of your new medication. If there is, then you may need to step-up to another level of medication in order to gain further control of your asthma symptoms. If you have any questions about the pulmonary function testing or the new medication, then you should certainly talk to your doctor to gain a better understanding of the current situation.