Answer to Question 1
ANS: D
A sweat chloride test result greater than 60 mEq/L is diagnostic of CF. Although bronchoscopy is helpful for identifying bacterial infection in children with CF, it is not diagnostic. Serum calcium is normal in children with CF. Urine creatinine is not diagnostic of CF.
Answer to Question 2
ANS: A
The earliest clinical manifestation of CF is a meconium ileus, which is found in about 10 of children with CF. Clinical manifestations include abdominal distention, vomiting, failure to pass stools, and rapid development of dehydration. History of malabsorption is a later sign that manifests as failure to thrive. Foul-smelling stools and recurrent respiratory infections are later manifestations of CF.