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Test Code Sweat CL Sweat Chloride

Important Note

Outpatients must be scheduled at 206-987-3860. Outside orders should be faxed to 206-985-3124.

Inpatients much be scheduled at 206-987-3694.  Inpatient procedures can be done at the bedside if necessary.

The procedure takes up to one hr, and there are no dietary restrictions. The child should be >48 hr old, non-febrile, > 2.5 kg (5.5 lbs), not on steroids or oxygen.

Additional Codes

Off Site collection use test code CL, Sweat

Clinical System Name

Sweat Chloride

Sample Requirements

Note: Sweat Collection must be scheduled with Chemistry at 206-987-3860 or 206-987-3694 for inpatients. The patient should be well hydrated, at least 48 hr old, and weigh at least 2.5 kg (5.5 lb). The test is contraindicated in patients who are receiving oral steroids, or are acutely ill.  The test cannot be performed in patients receiving oxygen. Contact Chemistry Lab for more information (206) 987-3860.  

Processing Instructions

Off-site collection: See CL, Sweat


STAT Performed TAT

M - F, day shift 0730-1330

same day


Performing Laboratory

Seattle Children's Laboratory


Department:  Chemistry

Location: Chem East

Phone Number:  (206)987-3860



Reference Range


Normal (mEq/L) <30
Borderline/Indeterminate (mEq/L) 30 - 59
Consistent with the diagnosis of CF (mEq/L)  ≥60




Method: Pilocarpine iontophoresis/ with chloride titration

Analytical Volume: 0.10 mcL or 75 mg


CPT Codes


Clinical Utility

The sweat test is used for diagnosis of Cystic Fibrosis