Understanding the issues with interpreting a FeNO measurement

There are certain factors that can influence the amount of nitric oxide that a patient exhales. Active eosinophilic inflammation associated with allergic asthma is one of them, but there are other factors that could lead this levels to be raised which could lead to a false positive result, including:

  • Tall height
  • Male sex
  • Rhinitis
  • Eosinophilic bronchitis
  • High nitrate diet
  • Rhinovirus infection
  • Low BMI

Equally, there are factors that can dampen the exhaled nitric oxide, leading to a false negative FeNO result, including:

  • Cigarette smoke
  • Intense physical activity
  • Young children
Mark as Understood

© Institute of Clinical Science and Technology (ICST) 2020

Support: admin@clinicalscience.org.uk