Sweat test

What is a sweat test?

Your doctor has asked us to give your child a sweat test. In this test, we collect a small amount of sweat from the skin and test it to see if your child has a condition called cystic fibrosis. Cystic fibrosis is a genetic disease that affects the lungs and digestive system.

How is it done?

To stimulate adequate sweat production a solution containing pilocarpine and a very small gentle electrical current is applied to your child's skin. The test is usually performed on the child's arm or leg. After sufficient sweat is collected, it is tested for its salt content. In most cases a high salt content indicates cystic fibrosis.

How long does it take?

The sweat test usually takes about one hour. However there are times when two tests are needed so two hours should be allowed for this appointment. The result of the sweat test is available later the same day. To obtain this result, please contact your doctor, not the laboratory.

Does it hurt? Is it safe?

Sweat testing is a very safe procedure and thousands of children have been tested in many countries without any problems. Usually only minor discomfort is experienced. Because the child's skin heats up over a small area during the test, there is a very slight risk of causing a minor skin inflammation. Young babies less than six weeks of age are most sensitive to this. In extremely rare circumstances, the heating of the skin has been known to cause a very small superficial burn.

On rare occasions, we cannot collect enough sweat for the test and we will have to repeat the test some weeks later.

• Sweat testing is a safe procedure.
• The test may have to be repeated if not enough sweat is collected.
• Should only be performed at a recognised centre for sweat testing.