TY - JOUR T1 - Inter-instrument variability in exhaled nitric oxide measurement and implications on test interpretation JF - European Respiratory Journal JO - Eur Respir J VL - 44 IS - Suppl 58 SP - P1007 AU - Jeffrey Pretto AU - Brenton Eckert AU - Jodie Simpson AU - Heather Powell AU - John Upham AU - Peter Gibson Y1 - 2014/09/01 UR - http://erj.ersjournals.com/content/44/Suppl_58/P1007.abstract N2 - Differences in measurement of fractional exhaled nitric oxide (FeNO) between instruments is well documented, but the clinical implications of these differences using the 2011 ATS FeNO interpretation guidelines (AJRCCM, 2011; 184:602) has not been described. Aims: To document inter-instrument variability in FeNO measurements from 3 devices and to assess the implications of this variability on how results are interpreted in an adult clinical cohort. Methods: Comparisons between a handheld device (NIOX MINO) and 2 chemoluminescence devices (Ecomedics CLD88-comparison A, and Sievers NOA 280i-comparison B) were made. Using ATS interpretative cut-point criteria of 25ppb and 50ppb, the diagnostic performance of the MINO in identifying abnormal FeNO results was assessed using the chemoluminescence systems as standards. Results: Mean (SD) difference for comparison A in 94 adults (18M:76F) across the 5-98ppb range was small at 0.2 (8.8)ppb. Interpretation agreement between devices was 94.7% using both cut-points. MINO tended to read lower for comparison B in 73 adults (33M:40F) across the 5-131ppb range with difference of 8.8 (9.6)ppb. Interpretation agreement was 87.7%. For both comparisons there were tight relationships with simple linear modelling enabling precise correction of inter-instrument differences (A: Y= 1.16x-3.81. R =0.94, p<0.01. B: Y= 1.25x-0.733. R = 0.98, p<0.01). Conclusions: FeNO measurements from the hand-held MINO device compare favourably with more expensive chemiluminescence analysers with simple corrections enabling comparable instrument readings. Inter-instrument differences resulted in 7% misclassification rate for clinical interpretation (12 of 167 subjects). ER -