Developing fractional exhaled nitric oxide (FeNO) predicted and upper limit of normal values for a disadvantaged population.

As single paediatric, adult, or all-age FeNO cut-off values used by current interpretive guidelines to define abnormality fail to account for factors that modify FeNO values, we propose predicted and ULN values for First Nations Australians aged 4-76 years. Creating age and height adjusted predicted and ULN values could be considered for other ethnicities.