4
The Sweat Test
The Sweat Test
What is a sweat test?
A sweat test measures the amount of salt in sweat. Your doctor has
asked for this test to rule out cystic fibrosis (CF) either because your
child had a positive result from the newborn screen or he/she suspects
that you may have CF. People with CF will have higher amounts of salt
than normal in their sweat.
What is cystic fibrosis?
Cystic fibrosis (CF) is a genetically inherited disease, in which a
person inherits two faulty copies of the CF gene from their parents.
The disease can affect a wide range of organs in the body, in particular
the lungs and digestive system, which often leads to a failure to grow
adequately in children. Early diagnosis of CF has been shown to lead
to earlier treatment and improved health outcomes. If you are
interested in more information, then your doctor can discuss it further
with you.
How does my child prepare for this test?
Before having this test, you may eat, drink, exercise and continue to
take any medications as usual. But please do not put creams or lotions
on your skin 24 hours before the test, as this will interfere with the
measurement.
©
Hamilton Health Sciences, 2010
PD 7300 – 12/2010
dpc/pted/SweatTest-trh.doc
dt/December 9, 2010
____________________________________________________________________________
2
The Sweat Test
How is a sweat test done?
The test is done by a specially trained technologist in two steps.
The first step involves sweat stimulation. It begins with the cleaning
of a small area of the skin on the arm or leg with gauze and water.
Pilocarpine, a solution that causes sweating, is then applied with gauze
to one area and a salt water solution is applied with gauze to another
area on the same arm or leg. An electrode is placed over each piece
of gauze and hooked up to a machine. The machine produces a mild
electrical current that helps to stimulate the sweating over the area
treated with the solution. You may feel a slight tingling in the area or
it may feel warm. The electrodes are left in place for 5 minutes.
The electrodes and gauze are then removed.
The Sweat Test
3
Are there any risks?
The electrical current may cause your skin to become slightly red.
What will the sweat test show?
Most of the time, the results will show either a normal or high salt level.
Occasionally a result may be unclear or there may be technical
problems such as not enough sweat was collected. If this happens,
your doctor may request that the test be repeated.
If your test is positive, then we will telephone the results to your doctor
by the next day. All other results of the sweat test will be sent to your
doctor by mail.
The second step of the test involves sweat collection. The stimulated
area of skin is cleaned again with gauze and water. A piece of fresh
gauze is placed over this area and secured with tape. The gauze will be
left in place for 30 minutes to allow enough sweat to be absorbed.
You will be allowed to wait in the waiting room over this period. After
30 minutes, the gauze will be removed and you will be allowed to leave.
The gauze will be taken to the lab to measure the salt content of the sweat.
__________________________________________________________________________________
________________________________________________________________________________
2
The Sweat Test
How is a sweat test done?
The test is done by a specially trained technologist in two steps.
The first step involves sweat stimulation. It begins with the cleaning
of a small area of the skin on the arm or leg with gauze and water.
Pilocarpine, a solution that causes sweating, is then applied with gauze
to one area and a salt water solution is applied with gauze to another
area on the same arm or leg. An electrode is placed over each piece
of gauze and hooked up to a machine. The machine produces a mild
electrical current that helps to stimulate the sweating over the area
treated with the solution. You may feel a slight tingling in the area or
it may feel warm. The electrodes are left in place for 5 minutes.
The electrodes and gauze are then removed.
The Sweat Test
3
Are there any risks?
The electrical current may cause your skin to become slightly red.
What will the sweat test show?
Most of the time, the results will show either a normal or high salt level.
Occasionally a result may be unclear or there may be technical
problems such as not enough sweat was collected. If this happens,
your doctor may request that the test be repeated.
If your test is positive, then we will telephone the results to your doctor
by the next day. All other results of the sweat test will be sent to your
doctor by mail.
The second step of the test involves sweat collection. The stimulated
area of skin is cleaned again with gauze and water. A piece of fresh
gauze is placed over this area and secured with tape. The gauze will be
left in place for 30 minutes to allow enough sweat to be absorbed.
You will be allowed to wait in the waiting room over this period. After
30 minutes, the gauze will be removed and you will be allowed to leave.
The gauze will be taken to the lab to measure the salt content of the sweat.
__________________________________________________________________________________
________________________________________________________________________________
4
The Sweat Test
The Sweat Test
What is a sweat test?
A sweat test measures the amount of salt in sweat. Your doctor has
asked for this test to rule out cystic fibrosis (CF) either because your
child had a positive result from the newborn screen or he/she suspects
that you may have CF. People with CF will have higher amounts of salt
than normal in their sweat.
What is cystic fibrosis?
Cystic fibrosis (CF) is a genetically inherited disease, in which a
person inherits two faulty copies of the CF gene from their parents.
The disease can affect a wide range of organs in the body, in particular
the lungs and digestive system, which often leads to a failure to grow
adequately in children. Early diagnosis of CF has been shown to lead
to earlier treatment and improved health outcomes. If you are
interested in more information, then your doctor can discuss it further
with you.
How does my child prepare for this test?
Before having this test, you may eat, drink, exercise and continue to
take any medications as usual. But please do not put creams or lotions
on your skin 24 hours before the test, as this will interfere with the
measurement.
©
Hamilton Health Sciences, 2010
PD 7300 – 12/2010
dpc/pted/SweatTest-trh.doc
dt/December 9, 2010
____________________________________________________________________________