RT Journal Article SR Electronic T1 Within-session variability as quality control for oscillometry in health and disease JF ERJ Open Research JO erjor FD European Respiratory Society SP 00074-2021 DO 10.1183/23120541.00074-2021 VO 7 IS 4 A1 Louise M. Harkness A1 Kieran Patel A1 Farid Sanai A1 Sandra Rutting A1 Alice M. Cottee A1 Claude S. Farah A1 Robin E. Schoeffel A1 Gregory G. King A1 Cindy Thamrin YR 2021 UL http://openres.ersjournals.com/content/7/4/00074-2021.abstract AB Oscillometry is increasingly adopted in respiratory clinics, but many recommendations regarding measurement settings and quality control remain subjective. The aim of this study was to investigate the optimal number of measurements and acceptable within-session coefficient of variation (CoV) in health, asthma and COPD.15 healthy, 15 asthma and 15 COPD adult participants were recruited. Eight consecutive 30-s measurements were made using an oscillometry device, from which resistance at 5 Hz (Rrs5) was examined. The effect of progressively including a greater number of measurements on Rrs5 and its within-session CoV was investigated. Data were analysed using one-way repeated-measures ANOVA with Bonferroni post hoc test.The CoV(Rrs5) of the first three measurements was 6.7±4.7%, 9.7±5.7% and 12.6±11.2% in healthy, asthma and COPD participants, respectively. Both mean Rrs5 and CoV(Rrs5) were not statistically different when progressively including four to eight measurements. Selecting the three closest Rrs5 values over an increasing number of measurements progressively decreased the CoV(Rrs5). In order for ≥95% of participants to fall within a target CoV(Rrs5) of 10%, four or more, five and six measurements were needed in health, asthma and COPD, respectively.Within-session variability of oscillometry is increased in disease. Furthermore, the higher number of measurements required to achieve a set target for asthma and COPD patients may not be practical in a clinical setting. Provided technical acceptability of measurements is established, i.e. by removing artefacts and outliers, then a CoV of 10% is a marker of quality in most patients, but we suggest higher CoVs up to 15–20% should still be reportable.Within-session variability of oscillometry indices is intrinsically higher in disease. Quality control should first focus on technical acceptability of measurements, i.e. by removing artefacts and outliers over reducing variability, and CoVs up to 15−20% should still be reportable. https://bit.ly/3w7qbIR