A mother brings her 2-month-old to the well-baby clinic. She mentions that when she kisses her baby, the infant’s skin tastes salty. What standard diagnostic test should the nurse prepare the mother for to screen for cystic fibrosis (CF)?

Choice A rationale A fecal-fat test is used to measure the body’s ability to break down and absorb fat. It is not a standard diagnostic test for cystic fibrosis (CF)6. Choice B rationale A sweat-chloride test is the standard diagnostic test for CF. People with CF have higher than normal levels of sodium and chloride in their sweat, which can make their skin taste salty. Choice C rationale A pulmonary-function test measures how well the lungs work and can be used to monitor lung disease in people with CF. However, it is not a standard diagnostic test for CF, especially in a 2- month-old infant. Choice D rationale A potassium chloride test is not a standard diagnostic test for CF6.