Nasal nitric oxide measurement is a non-invasive test used to assess the levels of nitric oxide in the nasal passages. This gas plays a crucial role in various bodily functions, including immune response and airway regulation. Elevated levels of nasal nitric oxide can indicate conditions like asthma or cystic fibrosis, while low levels may suggest sinusitis or other respiratory issues. The measurement is typically performed using a handheld device that captures exhaled air from the nose. Results can help healthcare providers diagnose and monitor respiratory conditions, guiding treatment decisions and improving patient outcomes.