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Having a Sweat Chloride Test

Before Your Test
The Sweat Chloride test is performed only at WakeMed Raleigh Medical Park located at 23 Sunnybrook Rd.  An appointment is necessary for this test.  Please call (919) 350-8238 if your doctor has not already made an appointment.  Click for more information and directions for the Raleigh Medical Park.

Make sure your child is well hydrated before this test is performed.  Encourage him or her to drink plenty of fluids in the twenty-four hours prior to the test.  If other tests are scheduled during the same appointment that require your child to fast, the sweat test should be rescheduled for another day. 

What to Bring
     • The completed WakeMed Physician Order Form
     • Your insurance card and information
     • Any papers your doctor tells you to bring
     • A favorite toy for your child to play with during the test

You may also bring a bottle or a sippy cup for your child to have during the test (provided this will not interfere with any other testing).
When you arrive
When you arrive for your child's sweat chloride test, report to the Patient Registration area.  At Patient Registration, you will be asked for information that is required for our records and insurance billing purposes.  We will also request your child’s name address, date of birth and weight.

Outpatient Testing
After leaving Patient Registration, you and your child will be called to the laboratory.  Here you can meet the members of your pathology team and ask any questions that you might have.

What is a Sweat Chloride Test?
A sweat chloride test measures the level of chloride (salt) in sweat.

How is the test performed ?
A small testing device with two electrodes is used to perform this test. The positive electrode is covered by gauze and saturated with pilocarpine (a drug that stimulates sweat). The negative electrode is covered with gauze and saturated with bicarbonate solution.  A very low level of electric current is applied for five to 12 minutes. This causes the pilocarpine to diffuse into the skin in that local area and causes the sweat glands in that area to secrete more sweat for a period of time. A paper disk is then placed over the test site and covered to obtain an airtight seal. After one hour, the disk is transferred to a weighing jar and then put in water to dissolve the salts. This solution is then analyzed for chloride.

Will this test hurt?
There is a slight warming of the area but no pain. Infants may cry because they will have to be held still.

How long will the test take?
The test will take approximately two hours.

How can I get the results?
After the specimen arrives in our laboratory, it will take our technologist team several hours to complete the analysis. The test results will be sent to your physician. Laboratory employees are not permitted to release test results to the patient.