Reconsidering the Diagnosis: Abnormal Sweat Chloride Tests in Non-CF Bronchiectasis.

Introduction: While the diagnosis of cystic fibrosis (CF) is often straightforward and reliant on correlation between genetic testing and clinical signs and symptoms, there is a subset where the distinction is not nearly as clearcut. This has previously been reported in patients identified through newborn screening but not meeting full CF diagnostic criteria, earning the label of CF Screen Positive, Inconclusive Diagnosis (CFSPID) instead. A homologous diagnostic category in adults is named CF Transmembrane Conductance Regulator-Related Disorder (CFTR-RD).