Feasibility and normal values of an integrated conductivity (Nanoduct™) sweat test system in healthy newborns

Background: Nanoduct((TM)) is a simple and practical sweat analysis system measuring conductivity in situ. It requires only three microlitres of sweat, making it especially applicable to newborns. Methods: We measured conductivity in 260 healthy term infants at the age of four days, and again at four weeks to determine the proportion of successful tests, test duration, and normal values for sweat conductivity in newborns. Results: Sufficient sweat was collected in 159/260 of four-day olds (61%), and in 225/239 of four-week olds (94%). Mean (sd) test duration was 27 (5) and 25 (5) min. Mean (sd, range) conductivity was 53 mmol/1 (16, 8-114) at age four days, and 36 (9, 12-64) at four weeks. Conclusions: Determination of sweat conductivity using Nanoduct (TM) cannot be recommended for four-day old newborns. However, at the age of four weeks the success rate is high (94%), and conductivity values at that age are comparable to older healthy children. (c) 2017 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.