Sweat test

Your child’s sweat test is scheduled for (date)___________    at (time) ___________  in the Laboratory on the 1st floor of the Children’s Wisconsin Clinics 1 Building.

Please stop at a Welcome desk for a badge and directions.

What is a sweat test?

A sweat test, also called a sweat chloride test is used to find out if a child has Cystic Fibrosis (CF). The test is being done because your child:

• Has symptoms sometimes seen in CF.
• Had a positive result on the Newborn Screen Test.

What is cystic fibrosis?

Cystic Fibrosis is a disease that causes the body to make thick, sticky mucus.  It most often affects the lungs and digestive system of the body.  Children with CF may have chronic lung infections or problems digesting their food. Symptoms can include:

• Chronic cough
• Wheezing
• Nasal polyps
• Some parents may notice a “salty” taste to the skin when they kiss their child.
• Frequent infections in the lungs
• Asthma
• Poor weight gain 

Note:  Many children will have some of these symptoms.  It does not mean they have CF. 

How is the test done?

The Sweat Test is a simple test that takes about one hour.

• A solution and electrodes are placed on the forearm.  
• Next, a weak electrical current is run through the electrodes. This stimulates the sweat glands in the skin to make sweat.  Your child may feel a tingling in the arm, but it does not hurt.
• The sweat is then collected on a piece of gauze for 30 minutes

How can I help?

If there is not enough sweat, the test may need to be done again. You can help your child produce enough sweat by:

• Having your child drink lots of water/milk the night before the test. 
• Bring a jacket, sweater or blanket for your child to wear during the test.
• Your child should not use soap or lotion on the arms the morning of the test.

If your child is a baby, you may give a bottle or nurse your baby while the sweat is collected.
If your child is a toddler or older, your child can play in a play area while the sweat is collected.  Do not leave the hospital during this time.

What happens after the test?

You will be given a card telling you what time the lab needs to take off the gauze.  Please check in at the desk a few minutes before this time to make sure the gauze is taken off on time.  A lab assistant will meet with you to take off the gauze and check your child’s arm. The area on your child’s skin may be red and raised after the sweat collection is done. This will fade in 2 to 3 hours. In rare cases, burns can occur at either electrode. They can be tiny black dots the size of pinholes or large reddened areas. If a burn does occur, your child will be given medical care to treat the area.

How do I get the test results?

It takes several hours for the test results to be ready. Your child’s doctor will get the sweat test results. You should call your child’s doctor to discuss the test results.

If you have questions or concerns: Contact the staff of the Cystic Fibrosis Center at Children’s Wisconsin with any questions you or your child may have about the test or about CF.