Review of the sweat test indications in a Brussels’ cystic fibrosis reference center

Sweat test is the gold standard of the diagnosis of cystic fibrosis (CF). The aim of our study was to identify the indications leading to perform a sweat test and those that led to the diagnosis of CF. METHODOLOGY: We collected data of all sweat tests performed between 2008, 1th of March and 2015, 28th of February. They were analyzed following Rosenstein diagnosis criteria (1998): clinical manifestations suggesting CF, positive neonatal screening (≥ 1 positive assay of immunoreactive trypsin) or familial history of CF. RESULTS: We reviewed 1,208 sweat tests over this period. Patients were aged from 13 days to 79 years. Indications were: clinical events (94.0%), a positive neonatal screening (3.7%) and a family history (2.3%). Over the 20 newly diagnosed patients, a positive neonatal screening was the main indication for the sweat test (55%). A positive neonatal screening (p<0.0001), a family history (p<0.0001) and pulmonary signs associated with digestive signs (p=0.004) were more frequently found in these patients. CONCLUSION: Sweat test indications are mostly clinical and mainly pulmonary. This study confirms that a sweat test should be performed in case of pulmonary manifestations suggesting CF especially if these are associated with digestive manifestations.