Medicine All of the following comments about cystic fibrosis (CF) are true except: A it can cause diarrhea B Staphylococcus aureus, Hemophilus influenzae, and Pseudomonas aeruginosa are common causes of respiratory infections. C A low concentration of sodium or chloride in sweat is diagnostic of CF. D Rhinosinustis is a common finding in CF. 💡 Explanation All of the following comments about cystic fibrosis (CF) are true except: ✓ Correct Answer: C. A low concentration of sodium or chloride in sweat is diagnostic of CF.