Cystic fibrosis (CF) is suspected in a toddler. Which test is essential in establishing this diagnosis?
Bronchoscopy
Serum calcium
Urine creatinine
Sweat chloride test
The Correct Answer is D
This test measures the amount of chloride in the sweat, which is abnormally high in people with cystic fibrosis (CF). CF is an inherited disorder that affects the cells that produce mucus, sweat, and digestive juices.

Choice A is wrong because bronchoscopy is a procedure that allows the doctor to examine the airways and lungs, but it is not essential for diagnosing CF.
Choice B is wrong because serum calcium is a blood test that measures the level of calcium in the blood, which is not related to CF.
Choice C is wrong because urine creatinine is a test that measures the amount of creatinine in the urine, which reflects the kidney function, but it is not relevant to CF.
Normal ranges for sweat chloride test are:
- Less than 40 millimoles per liter (mmol/L) for children and adults
- Less than 30 mmol/L for infants younger than 6 months
A sweat chloride level of more than 60 mmol/L is considered positive for CF.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is ["A","B","C","D"]
Explanation

These are all positive signs of pregnancy, which are definitive and can only be explained by the presence of a fetus.A positive sign of pregnancy is fetal movement palpated by the nurse-midwife.
Choice E is wrong because a positive hCG test is a probable sign of pregnancy, not a positive one.A probable sign of pregnancy is strongly suggestive of pregnancy but could have other causes.A positive hCG test could be caused by medications, tumors, or other conditions that affect the level of hCG in the blood or urine.
Some other probable signs of pregnancy are uterine enlargement, Hegar’s sign (softening of the lower uterine segment), Goodell’s sign (softening of the cervix), Chadwick’s sign (bluish discoloration of the cervix), ballottement (rebound of the fetus when tapped by the examiner’s finger), Braxton Hicks contractions (painless, irregular uterine contractions), and positive pregnancy test.
Some other positive signs of pregnancy are identification of fetal heartbeat, visualization of the fetus by ultrasound or x-ray, and verification of fetal movement by an experienced clinician.
Correct Answer is D
Explanation
Digoxin is a medication that helps improve the pumping function of the heart and reduces fluid retention in the lungs and other tissues. It is commonly used to treat congestive heart failure in infants.
Choice A is wrong because weighing the infant every day on the same scale at the same time is a way to monitor fluid balance, not an intervention to treat excess fluid volume.
Choice B is wrong because notifying the physician when weight gain exceeds more than 20 g/day is also a monitoring measure, not an intervention. Moreover, weight gain may not accurately reflect fluid volume status in some patients with heart failure due to poor nutrition and decreased appetite.
Choice C is wrong because putting the infant in a car seat to minimize movement may worsen the respiratory distress and increase the workload of the heart. The infant should be positioned in a semi-Fowler’s or Fowler’s position to facilitate breathing and reduce venous return.
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