Sweat testing and cystic fibrosis – Test performance before and after a quality improvement project in a South African tertiary hospital laboratory.

This article focuses on evaluating sweat test performance for cystic fibrosis (CF) diagnosis and the impact of a quality improvement project (QIP) aimed at reducing the quantity not sufficient (QNS) rates in a South African tertiary hospital laboratory. The study retrospectively audited sweat conductivity (Nanoduct®) and sweat chloride (Macroduct®) testing over two years, finding higher QNS rates in younger infants, malnourished, and acutely ill patients, with Nanoduct® showing lower QNS rates overall. Following the QIP—which included technologist training, clinician education, and patient preparation protocols—QNS rates improved modestly in older infants and children but remained challenging in younger infants. The authors recommend concentrating sweat testing among experienced technologists, prioritizing Macroduct® collection for improved proficiency and reliability, and ensuring patient readiness to optimize test outcomes.