Intestinal current measurement versus nasal potential difference measurements for diagnosis of cystic fibrosis: a case–control study

摘要

Background Nasal potential difference (NPD) and intestinal current measurement (ICM) are functional CFTR tests that are used as adjunctive diagnostic tools for cystic fibrosis (CF). Smoking has a systemic negative impact on CFTR function. A diagnostic comparison between NPD and ICM and the impact of smoking on both CFTR tests has not been done. Methods The sweat chloride test, NPD, and ICM were performed in 18 patients with CF (sweat chloride >60?mmol/l), including 6 pancreatic sufficient (PS) patients, and 13 healthy controls, including 8 smokers. The NPD CFTR response to Cl-free and isoproterenol perfusion (Δ0Cl-?+?Iso) was compared to the ICM CFTR response to forskolin/IBMX, carbachol, and histamine (ΔI_{sc, forskolin/IBMX+ carbachol+histamine}). Results The mean NPD CFTR response and ICM CFTR response between patients with CF and healthy controls was significantly different (p Conclusions ICM is superior to NPD in distinguishing between patients with CF who have a sweat chloride?>?60?mmol/l and healthy controls, including smokers. Neither NPD nor ICM differentiated between patients with CF who were PS from those who were PI. Smoking has a negative impact on CFTR function in healthy controls measured by NPD and challenges the diagnostic interpretation of NPD, but not ICM.