Sweat test
sweat test · sweat chloride test · cystic fibrosis test · sweat test for children
A little sweating is triggered on the skin of the arm, and the sweat is collected. The salt in it is measured. This helps check for cystic fibrosis.
If newborn screening showed a risk of cystic fibrosis, or for frequent bronchitis and pneumonia, poor weight gain, or greasy stools.
⏱ Duration: usually 30 to 60 minutes; results often come the same day
Be sure to tell your doctor
How to prepare
- Food. Usually no special prep. Feed your child as usual.
- Skin. On the test day, do not put creams or oils on the arms.
- Health. If your child is ill now, ask if the test should be moved.
- Kids. Bring a toy, a book, or cartoons. Your child needs to sit for about half an hour.
What to bring
- The referral
- Your child's documents
- The newborn screening report, if you have it
- A toy and a snack
How it goes
- The skin on the forearm is washed and dried
- Two small electrodes with gel are placed, and a weak current runs for about 5 minutes
- The electrodes are removed, and a sweat collector is attached to the spot
- Your child sits quietly for about 30 minutes with the arm covered
- The collector is removed and sent to the lab
What you'll feel
- Light tingling or warmth under the electrodes
- It does not hurt, but waiting can be boring for a child
- Afterward, the skin may be a little red
Afterwards
- The redness goes away in a few hours
- Results often come the same day or in 1 to 2 days
- Sometimes the test is repeated if too little sweat was collected
Common questions
Is the current safe for my child?
Yes. The current is very weak. It only helps the skin make sweat.
What if the result is borderline?
The doctor may order a repeat test or a genetic test.