Which of the following is NOT considered a pulmonary function test?

An electrocardiogram (ECG) is primarily used to assess the electrical activity of the heart, making it a tool for diagnosing cardiac conditions rather than pulmonary function. In contrast, other tests such as peak flow measurement, diffusion capacity, and spirometry are specifically designed to assess different aspects of lung function.

Spirometry measures the volume and flow of air that can be inhaled and exhaled, providing crucial data on lung capacity and airflow obstruction. Peak flow measurements are used to evaluate the maximum speed of expiration, which is particularly helpful in asthma management. Diffusion capacity assesses how effectively gases like oxygen move from the alveoli into the bloodstream, which is vital in determining the functionality of the respiratory membrane.

Thus, the classification of these tests is based on their purpose; while peak flow measurement, diffusion capacity, and spirometry are integral to pulmonary function assessment, an ECG serves a different diagnostic function related to the cardiovascular system.