Standards of care guidance for sweat testing; phase two of the ECFS quality improvement programme

More than five decades after the introduction of the quantitative pilocarpine iontophoresis technique, surveys still highlight inconsistencies in the performance and reporting of sweat tests in Europe. The sweat test remains key for the Cystic Fibrosis (CF) diagnostic pathway for all age groups, as it reflects the basic pathophysiological defect in the sweat gland. It is also critical following newborn screening as a confirmatory diagnostic step. Despite its importance, sweat test quality is variable whether performed in the laboratory or as a point of care test. The ECFS DNWG aims to improve sweat test performance, taking into account the barriers and issues identified in the European survey; the previous step in the ECFS sweat test project. This manuscript proposes a grading of sweat test guidance from "acceptable" to "optimal", aiming to pragmatically improve quality while taking into account local situations, especially in resource-limited settings.