Information for patients
This leaflet can be made available in other formats including large print, CD and Braille and in languages other than English, upon request.
Your child’s Doctor has advised that he or she should have a sweat test to help find the cause of his or her symptoms. This test may also be used for screening.
This leaflet tells you about what a sweat test is. This leaflet will also help you to explain to your child what will happen during and after the test.
What is a sweat test?
A sweat test measures the amount of salt (sodium chloride) in your child’s sweat.
Why does this test need to be carried out?
This test may be requested, for example, if your child:
- has frequent chest infections
- has frequent and unexplained pale stools (bowel motions or poos)
- has problems gaining weight
- is growing slowly.
The test can also be requested to screen your child if there is a history of cystic fibrosis (CF) in your family. It is important to diagnose this condition as soon as possible in order to begin treatment.
People with CF have a high amount of salt in their sweat. A normal result can help your child’s doctor rule out a diagnosis of cystic fibrosis.
A positive sweat test result may mean your child has cystic fibrosis. Your child’s Doctor will make a diagnosis from his or her clinical findings and all the test results.
What will happen during the sweat test?
You will be asked to bring your child to the Children’s Outpatients Department at University Hospital of North Tees. The test takes about 1 hour to complete.
No needles or injections are involved.
Special pads containing a chemical called pilocarpine, that stimulates (encourages) sweat production, are placed on your child’s lower arm or leg.
These are held in place with sticky tape and a small electric current is passed through the pad from a special battery box. This further stimulates the sweating process.
The pads are left in place for about 5 minutes and then removed.
There should be a red mark where the pilocarpine has stimulated the skin. This should fade within a few hours. The skin is then carefully washed with sterile water and dried. A plastic coil is then placed over the stimulated area and held in place.
You will be asked to wait for about 20 to 30 minutes for the sweat to be absorbed into the coil device. The exact time will depend on the amount of sweat produced. During this time, your child may read or play, but is not allowed to eat or drink in case the area comes into contact with any salt.
The coil is then removed and sent for examination in the laboratory.
Who will do the sweat test?
This test will be carried out by Biomedical Scientists (people trained to perform laboratory tests).
Does the test hurt?
The test is not painful, although some children may feel tingling on the arm or leg where the sweat has been collected.
When will I be told the results of the sweat test?
The results of the sweat test are usually sent to the Doctor who requested them. The Consultant will then contact you, either by telephone or by letter with results of the sweat test.
The test results will usually show:
- an abnormal (high)
- a normal
- an equivocal (uncertain) salt level in the sweat. You will be advised if your child will need to be seen again.
In some cases, the test may need to be repeated, for example, if the result is uncertain or not enough sweat was collected. Many Doctors also like to confirm an abnormal sweat test with a second sweat test.
If you need further advice or have any questions or problems about the sweat test, please contact the appropriate number below:
Children’s Outpatient Department
University Hospital of North tees
Telephone: 01642 624527
Opening hours: 9:00am to 5:00pm (Monday to Friday)
Comments, concerns, compliments or complaints
Patient Experience Team (PET)
We are continually trying to improve the services we provide. We want to know what we’re doing well or if there’s anything which we can improve, that’s why the Patient Experience Team (PET) is here to help. Our Patient Experience Team is here to try to resolve your concerns as quickly as possible. The office is based on the ground floor at the University Hospital of North Tees if you wish to discuss concerns in person. If you would like to contact or request a copy of our PET leaflet, please contact:
Telephone: 01642 624719
Freephone: 0800 092 0084
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Email: [email protected]
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Telephone: 01642 617617
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Telephone: 01642 383551
Email: [email protected]Privacy Notices
This leaflet has been produced in partnership with patients and carers. All patient leaflets are regularly reviewed, and any suggestions you have as to how it may be improved are extremely valuable. Please write to the Clinical Governance team, North Tees and Hartlepool NHS Foundation Trust, University Hospital of North Tees, TS19 8PE or:
Email: [email protected]
Leaflet reference: PIL1298
Date for review: 10 March 2024