Question

The physician has ordered a sweat test for a child suspected of having cystic fibrosis. A positive sweat test is based on: A. Chloride level B. Potassium transport C. Serum sodium D. Calcium level

Short answer

Answer: A. Chloride level

Step-by-step solution

Understanding the options

First, let us briefly analyze each substance mentioned in the options: A. Chloride level B. Potassium transport C. Serum sodium D. Calcium level

Identifying the correct factor for a positive sweat test

To determine the correct answer, recall that a sweat test is a diagnostic test for cystic fibrosis, which is characterized by the defective transport of chloride and other ion channels, leading to an excess of salt in the sweat. Hence, among the given options, the correct factor for a positive sweat test is: A. Chloride level The high levels of chloride in the sweat are indicative of a positive sweat test, and this is used to diagnose cystic fibrosis in children.