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At a glance - FeNO testing in asthma

To consider how and when we use FeNO testing, we need to go to the definition of asthma. Both BTS/SIGN1 and GINA2 define it as a predominantly inflammatory disorder of the airways with airway hyperresponsiveness and variability in symptoms. Nitric oxide is a gas involved in the respiratory process and is present in the atmosphere in very small amounts (parts per billion). It can be easily measured in exhaled breath using a fractional exhaled nitric oxide (FeNO) test. A raised FeNO is associated with eosinophilic inflammation of the airways, which is the characteristic inflammation of asthma. It can therefore be used as a test to support a diagnosis of asthma. The BTS/SIGN and NICE guidelines for asthma diagnosis currently make different recommendations on when FeNO should be used.

To assist with FeNO delivery in primary care, PCRS is hosting a variety of resources - this article outline each of these resources and provides a brief update on FeNO testing in asthma.