This is an observational study which will collect sweat chloride values from approximately 1000 cystic fibrosis subjects who are currently on cystic fibrosis transmembrane conductance regulator (CFTR) modulators. This study will require one visit to an MUSC clinic which will last approximately 2 hours. Compensation is provided.

Based on the research priorities identified by Cystic Fibrosis families and clinicians, the goal of the STOP PEDS randomized controlled trial is to evaluate the long- and short-term safety and efficacy of the antibiotic strategies in the management of outpatient Pulmonary Exacerbation in children with Cystic Fibrosis.