The study was conducted to evaluate the clinical application of exhaled nNO in distinguishing between CRSwNP and CRSsNP in consideration of patients’ atopic status.

Eighty-eight patients with CRS and 20 healthy volunteers were recruited for this study. The exhaled nNO level was measured by using a hand-held device.

The mean ∓ SD levels of nNO in patients with CRSsNP were significantly higher than those in patients with CRSwNP, whereas patients with CRS exhibited lower levels of nNO compared with the control subjects. Patients with atopy and with and without nasal polyps showed significantly higher levels of nNO compared with patients without atopy. The stories of nNO were negatively correlated with the Lund-Mackay scores in both atopic and nonatopic patients with CRS. Receiver operating characteristic curves differentiated patients as CRSwNP, CRSsNP, healthy controls, and atopic and nonatopic subgroups, with acceptable sensitivity and specificity.

The study concluded that the exhaled nNO levels can be used to distinguish between patients with CRSwNP and patients with CRSsNP. However, the patient’s atopic status influenced nNO as a diagnostic or monitoring biomarker in CRS.