OBJECTIVE: To assess whether nasal nitric oxide (nNO) levels differ between 
healthy and sick sinuses in chronic rhinosinusitis (CRS). A secondary aim was to 
assess whether nNO levels change after treatment of CRS and whether there is an 
association with radiological findings or symptoms.
METHOD: Three groups of 12 participants each were examined: patients with CRS 
without polyposis (CRS group), patients with symptoms of CRS but radiologically 
normal sinuses (symptoms-only), and healthy controls. Measurements of nNO were 
carried out using aspiration method and humming maneuver. All participants 
completed the Sino-Nasal Outcome Test (SNOT-22). A second nNO measurement was 
done after treatment in the CRS group (n = 9) and the healthy control group (n = 
12).
RESULTS: Nasal NO did not differ between any of the groups with any of the 
measurement techniques. There was a trend toward lower nNO values in the CRS 
group compared with the symptoms-only group and healthy controls, but it did not 
reach statistical significance. The SNOT-22 demonstrated inferior values for the 
CRS and symptoms-only groups compared with the healthy controls. At follow-up, 
no statistically significant change was found for the nNO measurements in either 
group.
CONCLUSION: Irrespective of occluded or open ostiomeatal complexes, no 
statistically significant differences in nNO were found in CRS compared with 
healthy controls using aspiration and humming methods. Treatment of CRS improved 
sinus patency without accompanying a significant change in nNO. This study can 
therefore not conclude that nNO can be used as a diagnostic tool for CRS without 
polyposis.