In this video, you’ll see how to perform a Bronchial FeNO50 test — a standardized measurement of nitric oxide in the exhaled breath, focused on large airway inflammation. The FeNO50 test helps clinicians evaluate respiratory inflammation, a key marker in conditions such as asthma.

First, we prepare the FeNO measurement device and accessories according to the manufacturer’s instructions, ensuring a clean mouthpiece and properly calibrated equipment. The test setup is designed for accuracy and patient comfort. Next, the operator explains the procedure to the patient, emphasizing the importance of a steady breath flow throughout the measurement.

The patient sits upright and places the mouthpiece in their mouth. With guidance from the clinician or technician, the patient inhales deeply to fill their lungs, then exhales slowly and steadily into the FeNO device at a controlled flow rate. The device accurately measures the fractional exhaled nitric oxide concentration as parts per billion (ppb). This specific flow rate — 50 mL per second — targets nitric oxide levels from the bronchial region of the large airways.

Throughout the measurement, visual and audio feedback guides the patient to maintain consistent breath technique. Once the exhalation is complete, the device displays the FeNO50 value immediately. Clinicians can repeat the test if needed to ensure reliable results.

The FeNO50 reading you get from this test serves as a non‑invasive biomarker for airway inflammation and supports clinical decisions around respiratory diagnosis and treatment.