Lung function test or spirometry is a test used to check the condition and function of the respiratory tract. In this test, the amount and speed of air that is inhaled and breathed by the patient will be measured. Spirometry helps doctors diagnose diseases related to the respiratory tract, and observes the development of the patient's condition for the therapy given Spirometry is carried out using an instrument called a spirometer. Some parameters that can be measured by the spirometer include: Forced expiratory volume in one second (FEV1). FEV1 is the amount of air that is blowing in one second. Forced vital capacity (FVC). FVC is the amount of air that can be breathed in one breath. The FVC / FEV1 ratio is a value that indicates what percentage of lung air capacity can be exhaled in 1 second. Spirometry examination is performed to assess respiratory disturbances, which are divided into two, namely: Obstructive airway disease. In this case, the body's ability to exhal