Fractional Exhaled Nitric Oxide Testing

**Definition:** Test to measure the levels of NITRIC OXIDE (an ENDOTHELIUM-DEPENDENT RELAXING FACTOR) in the exhaled air. FeNO test is used to determine levels of inflammation in the pulmonary ENDOTHELIUM often associated with endothelium associated diseases, e.g., ASTHMA.

**Tree numbers:** - E01.370.100.500

**Synonyms:** - FeNO Test - Exhaled Nitric Oxide Test