This test measures the amount of chloride in your child’s sweat. Chloride is one of several chemicals in the body called electrolytes. Electrolytes help control the amount of fluid in your child’s body and the way the muscles, nerves, and organs work. Your child needs the right balance of chloride and other electrolytes in his body to stay healthy. The balance of electrolytes in the body can be affected by food, medicines, drinking too much or too little water, or problems with your child’s lungs, kidneys, and other organs.
This test is done to diagnose cystic fibrosis. Cystic fibrosis (CF) is a disease that causes the body to make thick, sticky mucus. The thick mucus blocks airways, damages the lungs, and makes it hard to breathe. People with CF have more chloride (salt) in their sweat than someone who does not have CF.
Usually no preparation is needed for this test. Talk to your healthcare provider if you have any questions about the test.
To do the sweat test, a small wire is put on the skin. A weak electrical current causes the area to sweat. The sweat is collected and tested in a lab. This test does not hurt.
Ask your healthcare provider when and how you will get the result of the test.
A positive sweat chloride test means that it is likely that your child has cystic fibrosis.
Test results are only one part of a larger picture that takes into account your child’s medical history and current health. Sometimes a test needs to be repeated to check the first result. Talk to your healthcare provider about the result and ask questions, such as: