Sweat Chloride test
Why do we do this test?
For the diagnosis of cystic fibrosis
Specimen Type
Sweat sample collected using special sweat stimulation procedure
Instructions for specimen collection & Patient preparation
Patient preparation- No special preparation needed, instructed to avoid applying creams or lotions to skin 24 hours & well hydration before the procedure is preferred.

However, the sweat test should be deferred in babies <7 days old and/or <2 kg in weight, subjects who are dehydrated, systemically unwell or who have marked eczema or edema, subjects who are on oxygen by an open delivery system (this does not apply to head-box or nasal prong oxygen)

Specimen collection- Pilocarpine is delivered to a small area of sweat glands on the arm by iontophoresis. The stimulated sweat produced from this area is collected directly into a micro duct for chloride analysis.

Specimen transportation & Processing
If analysis is not to be carried out immediately, or if the sample must be transported to a different site for analysis, it is recommended that sweat is transferred to a labeled plain glass capillary tube. An air gap should be left at both ends, which are then sealed with plasticine to prevent evaporation.
Specimen storage & stability
4°C (refrigerated)
Specimen storage duration
maximum of 3 days
Reference Intervals & Target Values
Critical Limits
Possible Pre-analytical Errors
Contamination of sweat (Chloride containing local anesthetic solutions & skin antiseptics)
Evaporation of sweat during storage
Analysis of sweat sample with inadequate volume
Possible Analytical Errors
Available Government Laboratories
Lady Ridge way Hospital for Children- Colombo 08, Chemical pathology laboratory
Recommended turnaround time
Sweat sample collection by stimulation takes 30-40 minutes.
Report will be available on the same day

Test Method
Coulometric titration



Last Updated : 2020-09-23 03:21:36






College of Chemical Pathologists of Sri Lanka

No.112, Model Farm Road, Colombo 08.  Hotline : +94 76 7044871  Email : colchempath@gmail.com

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