Introduction/Aim Fractional exhaled nitric oxide (FeNO) is used as a non‐invasive measure of eosinophilic airway inflammation. It is unknown how appropriate the recommended FeNO cut‐off ranges are for Aboriginal and/or Torres Strait Islander patients. Our aim was to assess the distribution of healthy Aboriginal and/or Torres Strait Islander FeNO results according to current American Thoracic Society cut‐off guidelines.

Methods We measured FeNO (using Aerocrine NioxMINO) in 991 Indigenous children and young adults (aged 3 to 25 years) from seven Queensland communities. Questionnaires and medical charts were reviewed to identify healthy participants (no respiratory and/or atopic illness ever).

Results Acceptable FeNO measurements were achieved by 553 children (≤12 years) and 288 adults (>12 years). Participants with a history of respiratory and/or atopy conditions were excluded resulting in a healthy cohort of children (n=401, 72.5%) and adults (n=193, 67%). The geometric mean FeNO results for children and adults were 11.1ppb and 12.5ppb respectively. Table 1 summarises the distribution of healthy FeNO results for each ethnic group according to current cut‐off ranges.

Conclusion Although the majority of participants had FeNO results within the age‐respective normal ranges, we found a proportion of healthy participants with elevated FeNO results in all groups. The greatest proportion of elevated results was seen in Torres Strait Islander children and adults, and Aboriginal/Torres Strait Islander children. This suggests that the recommended cut‐off ranges may not be appropriate for these groups. Further investigation is still needed.