Background. Low nasal nitric oxide (nNO) has been reported in subjects with primary ciliary dyskinesia (PCD). Thus, nNO measurement has been proposed as a diagnostic tool to screen for PCD. The best validated method for nNO assessment is aspiration at a constant flow rate from one naris (Am J Respir Crit Care Med 2005;171:912-30). Traditionally, nNO is obtained using stationary chemiluminescence analysers. Hand-held electrochemical devices have been used in PCD for nNO analysis using the nasal exhalation method (silent and humming exhalation). No study compared nNO measured using continuous nasal aspiration in PCD and healthy subjects by a hand-held device.
Aim. To find out whether nNO measured by a hand-held analyser using the continuous aspiration method discriminates PCD from healthy subjects.
Methods. Twenty-three PCD patients (median age, 15.8 yrs; range, 4.6-32.8) and 23 healthy controls (age, 15.7 yrs; range, 4.3-32.1) measured nNO with a hand-held electrochemical device (NIOX MINO®, Aerocrine AB) during oral breathing through a mouthpiece.
Results. Median (range) nNO values were 12 (5-62) and 506 (215-777) ppb in PCD and controls, respectively (p < 0.001). Sensitivity and specificity at different cut-off points for nNO are reported in the Table.

Cut-off points (ppb)Sensitivity (%)Specificity (%)

Conclusion. Measurement of nNO by the hand-held device using the continuous aspiration method has an excellent sensitivity and specificity in distinguishing PCD from healthy subjects. Its wider use might result in an increased number of detected individuals suspected to have PCD.