Abstract: A portable hand-held spirometer is disclosed for use in taking respiratory tests and storing and displaying test results. The configuration of the spirometer includes handgrips that are positioned to ensure that the user is properly positioned to provide maximum breathing required for valid test results to be obtained. The spirometer also includes a progressively illuminated indicator that can be viewed by the user during a test to provide an indication in real-time to the user of the expected/desired duration of the exhalation or inhalation test. The indicator is completely illuminated only when the measured accumulated volume of air passing through the spirometer equals a predicted volume determined based on the age, gender, height, weight and ethnicity of the user stored in the spirometer. The structures and arrangement of a turbine assembly and sensors is also disclosed. Further, a method of receiving, storing and displaying information on the spirometer via a color touch screen display is also disclosed.