| The majority of studies indicate that more than 95% of PCD patients have very low nasal NO, confirming its suitability as a screening test |
| The small number of PCD patients with reportedly normal nasal NO require further evaluation, first to confirm the diagnosis of PCD and then to explain the atypical NO level in this group |
| Outstanding questions regarding NO in PCD |
| Is NO low throughout the airway, or only upper respiratory tract? |
| What mechanisms underlie low NO levels? |
| Is there a mechanistic link between ciliary beating and NO biosynthesis? |
| What are the implications of low NO in PCD? (e.g. are there effects on innate immunity?) |
| Does augmenting airway NO benefit patients? |
PCD: primary ciliary dyskinesia.