Outcomes of Sweat Conductivity Testing and Referral Patterns for Cystic Fibrosis: A 10-Year Retrospective...

Cystic fibrosis (CF) is an autosomal recessive disorder. Sweat testing is a cornerstone of CF diagnosis and remains essential in settings where nationwide screening and registries are limited.

We performed a retrospective single-center analysis of all patients referred for sweat testing in our laboratory between May 2015 and May 2025 (n=567). Sweat induction and collection were performed using the Macroduct® system, and analysis was conducted via the Sweat-Chek™ Analyzer (Model 3120, ELITechGroup). Statistical analysis was performed using Jamovi software (version 2.3.28).

The cohort included 302 males (53%) and 265 females (47%), with a mean age of 36.3 ±49.2 months (Median: 14; IQR: 4-48). The primary indications for referral were respiratory manifestations (57%), followed by gastrointestinal symptoms (14.1%), failure to thrive (6.2%), and others (4.2%). Asymptomatic individuals with no symptoms recorded at referral (18.2%). Diagnostic outcomes revealed that 83.4% of participants had normal results, 11.3% were positive, and 3% were borderline. A "quantity not sufficient" (QNS) rate of 2.3% was observed.

In this single-center referral cohort, most sweat test results were normal, with an overall positive rate of 11.3% and low QNS rates that are benchmark favorably against published quality targets. Clear referral pathways and strengthened early-life evaluation (including expansion of screening access) may support earlier diagnosis and reduce disease burden.