Our laboratory performs sweat testing according to the Cystic Fibrosis Foundation-approved manner. We may also order testing for changes in the cystic fibrosis gene.
What happens during a sweat test?
The sweat test determines the amount of chloride (salt) in the sweat. In the first part of the test, a colorless, odorless chemical, known to cause sweating, is applied to a small area on an arm or leg. An electrode is then attached to apply a weak electrical current that stimulates sweating. Patients may feel warmth or a tingling sensation in the area. This part of the procedure lasts approximately five minutes.
The second part consists of cleaning the stimulated area and collecting the sweat on a piece of filter paper or gauze, or in a plastic coil. Thirty minutes later, the collected sweat is sent to a hospital laboratory for analysis. The entire collection procedure takes approximately one hour.
What do you learn from the sweat test?
This test may help rule out the presence of CF, an inherited disorder of the lungs, intestines, and sweat glands. If the test is positive the patient will need evaluated at a CF center.
Is there any special preparation for the sweat test?
There are no restrictions on activity or diet, or any other special preparations before the test. However, you should not apply creams or lotions to the skin 24 hours before the test. All regular medications may be continued. Patients should be well hydrated when the sweat test is done. If the patient is acutely ill, we will usually reschedule the test.
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