Katherine Keenan1, Julie Avolio2, Claudia Rueckes-Nilges3, Elizabeth Tullis4, Tanja Gonska5, Lutz Naehrlich6. 1. Division of Paediatric Gastroenterology, Hepatology and Nutrition, University of Toronto and Physiology and Experimental Medicine, Research Institute, the Hospital for Sick Children, Toronto, Ontario, Canada. Electronic address: katherine.keenan@sickkids.ca. 2. Division of Paediatric Gastroenterology, Hepatology and Nutrition, University of Toronto and Physiology and Experimental Medicine, Research Institute, the Hospital for Sick Children, Toronto, Ontario, Canada. Electronic address: Julie.Avolio@sickkids.ca. 3. Department of Pediatrics, Justus-Liebig-University Giessen, Giessen, Germany. Electronic address: claudia.rueckes-nilges@paediat.med.uni-giessen.de. 4. Department of Medicine, University of Toronto and Division of Respirology and Keenan Research Centre of Li Ka Shing Knowledge Institute St. Michael's Hospital, Toronto, Ontario, Canada. Electronic address: TULLISE@smh.ca. 5. Division of Paediatric Gastroenterology, Hepatology and Nutrition, University of Toronto and Physiology and Experimental Medicine, Research Institute, the Hospital for Sick Children, Toronto, Ontario, Canada. Electronic address: tanja.gonska@sickkids.ca. 6. Department of Pediatrics, Justus-Liebig-University Giessen, Giessen, Germany. Electronic address: lutz.naehrlich@paediat.med.uni-giessen.de.
Abstract
BACKGROUND: The current practice of averaging the nasal potential difference (NPD) results of right and left nostril measurements reduce inter-individual variability but may underestimate individual CFTR function. METHODS: Best NPD response to Cl(-)-free and isoproterenol perfusion (=largest ΔPD(0Cl/Iso)) from the right and left nostril was compared to the average result in 13 cystic fibrosis (CF), 78 query-CF patients and 22 healthy controls from 2 cohorts. RESULTS: Despite moderate to good correlation (p<0.001) between right and left measured ΔPD(0Cl/Iso), we observed large differences in some individuals. A comparison of average versus best ΔPD(0Cl/Iso) showed only moderate agreement (Giessen κ=0.538; Toronto κ=0.607). Averaging ΔPD(0Cl/Iso) showed a lower composite chloride response compared to best ΔPD(0Cl/Iso) and altered diagnostic NPD interpretation in 30 of 113 (27%) subjects. CONCLUSIONS: The current practice of averaging the NPD results of right and left nostril measurements leads to an underestimation of the individual CFTR function and should be reconsidered.
BACKGROUND: The current practice of averaging the nasal potential difference (NPD) results of right and left nostril measurements reduce inter-individual variability but may underestimate individual CFTR function. METHODS: Best NPD response to Cl(-)-free and isoproterenol perfusion (=largest ΔPD(0Cl/Iso)) from the right and left nostril was compared to the average result in 13 cystic fibrosis (CF), 78 query-CF patients and 22 healthy controls from 2 cohorts. RESULTS: Despite moderate to good correlation (p<0.001) between right and left measured ΔPD(0Cl/Iso), we observed large differences in some individuals. A comparison of average versus best ΔPD(0Cl/Iso) showed only moderate agreement (Giessen κ=0.538; Toronto κ=0.607). Averaging ΔPD(0Cl/Iso) showed a lower composite chloride response compared to best ΔPD(0Cl/Iso) and altered diagnostic NPD interpretation in 30 of 113 (27%) subjects. CONCLUSIONS: The current practice of averaging the NPD results of right and left nostril measurements leads to an underestimation of the individual CFTR function and should be reconsidered.
Authors: Izabela Rocha Sad; Laurinda Yoko Shinzato Higa; Teresinha Leal; Raisa da Silva Martins; Ana Claudia de Almeida; Eloane Goncalves Ramos; Giselda Maria Kalil de Cabello; Maria Virginia Marques Peixoto Journal: J Clin Med Res Date: 2015-12-03