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A sweat test measures the amount of salt chemicals (sodium and chloride) in sweat. It can help diagnose cystic fibrosis. People with cystic fibrosis have 2 to 5 times the normal amount of sodium and chloride in their sweat.
During the sweat test, medicine that causes a person to sweat is applied to the skin. This is usually done on the arm or thigh. The sweat is collected on a paper or gauze pad. Then the amount of salt chemicals in the paper or gauze is measured in a lab. In most cases, chloride (sweat chloride) is measured.
Your child may need more than one sweat test to confirm whether he or she has cystic fibrosis.
The sweat test is done to help diagnose cystic fibrosis. It also may be used to test children with a family history of cystic fibrosis and for anyone with symptoms of cystic fibrosis.
You don't need to do anything to prepare before your child has this test. Your child may eat, drink, and exercise normally before the test. If your child takes any medicines, he or she can take them on the usual schedule.
The sweat test is usually done on a baby's arm or thigh. On an older child or adult, the test is usually done on the inside of the forearm. Sweat is usually collected and analyzed from two different sites.
This test does not cause pain. Some children feel a light tingling or tickling when the electric current is applied to the skin.
The sweat test usually takes 45 minutes to 1 hour.
Your child will probably be able to go home right away. Your child can go back to his or her usual activities right away.
Follow-up care is a key part of your child's treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse call line if your child is having problems. Ask your doctor when you can expect to have your child's test results.
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Adaptation Date: 5/5/2021
Adapted By: Alberta Health Services
Adaptation Reviewed By: Alberta Health Services
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