Nasal nitric oxide (nNO) in paediatric primary ciliary dyskinesia (PCD) and in healthy children - On the lookout for optimal cut-off and reference range

Introduction: PCD is a rare and chronic respiratory disease ultimately leading to bronchiectasis and impairment of lung function. In spite of advanced diagnostic tools (electron microscopy, high-speed video microscopy, immunofluorescence, genetic testing) confirming a diagnosis of PCD in children can cause difficulties. nNO is well-established screening test for PCD, but reference ranges and cut-off values in children are still scarce. Preliminary results from our center are presented. Material and Methods: Hand-held electrochemical nNO analyzer in 5 ml/s nasal aspiration mode during tidal breathing with mouthpiece was used. During 2006 – 2015 19 patients were admitted for suspected PCD (median age: 7 y.), in this group PCD was confirmed in 4 patients (2 girls, age at diagnosis: 6 and 10 y., 2 boys: both 12 y. old) and ruled out in 7 patients; the remaining 8 patients are still followed-up with no definite diagnosis. The control group consisted of 7 subjects: 6 girls and 1 boy (median age: 8.7 y.; IQR 8.3 – 10.7). Results: The median nNO concentrations were: 84 (IQR: 29-201) ppb in PCD patients and 743 (IQR: 585 – 866) ppb in control group (p Conclusion: We suggest nNO cut-off