Sweat Chloride Test :: Nationwide Children's Hospital

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Sweat Chloride Test

A sweat chloride test is done to find out how much chloride is in your child's sweat. Too much chloride in the sweat is one sign of some diseases. The results of the test will help your child’s doctor find out what is causing your child's problem.

How to Prepare for the Test

  • If your child is old enough, explain the test to him or her.
  • Bring a sweatshirt, coat or a heavy blanket to keep your child warm during the test so he will sweat.
  • Bring something to keep your child entertained while the test is being done (books, toys, or games).
  • Change your child's diaper, if needed, before the test so that he can stay bundled.
  • Be prepared to stay about 2 hours.

How the Test is Done

Image of sweat chloride test

Picture 1: Having a Sweat Chloride test.
  • A lab technician will select an area on the child's arm or leg for the test. This area will be cleaned with alcohol pads and then dried with gauze (Picture 1).
  • Two electrodes (two small disks) with a gel are applied to the area and held in place with Velcro® straps.
  • A machine that gives off a small amount of electricity is attached to the electrodes. This causes your child to sweat. There may be a slight pricking feeling at this time, which is normal. However, if it gets uncomfortable for him or her, tell the technician. This part of the test takes about 5 minutes.
  • The electrodes and machine are then removed and the arm is washed again with deionized water. A disk containing a tube to collect sweat is put exactly where one of the electrodes was and held in place by the Velcro strap. Plastic wrap or tape may be used to help hold the disk in place.
  • The disk is left in place for 30 minutes, then it is removed and the amount of sweat collected is measured while the procedure is done again on the other arm or leg.
  • After the second collector is in place, you and your child will go back to the waiting room. Please keep your child covered and warm while the test is going on. The child may move around, but try to keep him calm. Your child must stay warm during the collection time.
  • Do not leave the waiting room. If the child is not there when the collector needs to be taken off, the test will need to be redone.
  • The tube containing the sweat is taken off. The sweat is put in a small test tube.
  • The Velcro straps are undone and the disk is taken off.
  • The second test is done just like the first.

Warnings

There is a rare chance the electrodes may burn your child’s skin or your child may have a reaction to the chemical used in the test. If any of these things happens, tell your child’s doctor, nurse or lab technician immediately.

During the Test

Your child must stay covered and warm for 30 minutes while the sweat collector is on. Quiet entertainment will help keep him covered and content in bed or on your lap.

After the Test

  • The tubes containing the sweat are sent to the lab. The results of the test will be sent to your child’s doctor.
  • The doctor will explain the results of the test to you in 2 to 4 days.
  • If burning, redness, blisters, or irritation appear on your child’s skin, contact your child’s doctor.

If you have any questions, be sure to ask your child’s doctor or technician.

 

Sweat Chloride Test (PDF)

HH-III-62 7/83, Revised 7/15 Copyright 1983, Nationwide Children’s Hospital

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