FeNO Detection in Asthma Diagnosis: A New Technology Approach

1. Asthmatic patients and healthy individuals who fulfilled the inclusion criteria were categorized and assigned identification numbers. 2. The basic demographic and health-related information of the subjects was documented, including age, sex, height, weight, respiratory symptoms, medical history, allergy history, disease diagnosis, comorbidities, medication history, smoking history, lung function test results, and other relevant examinations. 3. Pre-testing requirements and preparations included: * Abstaining from all medications (including glucocorticoids, type II inflammatory monoclonal antibodies, leukotriene receptor antagonists, antihistamines, decongestants, hypertonic saline, bronchoconstrictor/diastolic agents, NO synthase inhibitors, and NO donor drugs such as nitroglycerin or L-arginine) for a duration of six hours prior to the test; * Fasting for three hours before the test; * Avoiding all forms of liquid intake (including alcohol and coffee), smoking (both active and passive), strenuous physical activity (such as running or aerobic exercise), and any respiratory diagnostic or therapeutic procedures (including pulmonary function tests and aerosol inhalation) for one hour prior to the test. 4. The researcher verified the subjects' compliance with the aforementioned testing requirements and proceeded with testing for those who met the criteria. Testing was uniformly scheduled during daytime hours. 5. Each participant underwent testing using both the moisture method and the online method, with the order of tests determined randomly via a randomization table to mitigate potential sequential effects. Each test was conducted in accordance with the ATS/ERS Technical Standard for the Determination of Exhaled Nitric Oxide (2005) and the operational guidelines for the equipment. Subjects were instructed to maintain an upright position and to repeat each test three times while in a resting state. A resting period of at least 30 seconds was mandated between tests, provided the subjects experienced no discomfort. The total duration of the testing procedure was anticipated to be approximately 20 minutes per individual.