Sweat Chloride

Sunquest Code:SWECL  
Epic Code:LAB1726Epic Name:Sweat ChlorideE Analysis
Order Instructions:Order screen as SWCLSC and Confirmatory as SWCLC.
Synonyms:Cystic Fibrosis Sweat Test; Pilocarpine Iontophoresis
Methodology:Sweat stimulation by Pilocarpine iontophoresis; chloride by coulometric titration
CPT Code:89230
Test Includes:Macroduct sweat collection: Sweat stimulation, collection, and chloride analysis. Screening using CF indicator patch placed over stimulated area for collection of sweat.
Turnaround Time:Sweat Chlorides are scheduled and collected by the Acute Care Lab, Mon-Fri.
Special Instructions:To schedule outpatient collections, contact the Pediatric Specialty Clinic Call Center at 612-365-6777. To schedule inpatient collections, contact the Sweat Chloride Laboratory at 612-365-8053. 24 hour notice is required for inpatient scheduling requests.

Collection Instructions

Specimen:Fluid, sweat
Optimal Volume:75 mg sweat
Minimum\Peds Volume:15 mg sweat
Patient Preparation:Patient must be older than 48 hours of age or greater than 6.6 lbs (3 kg). Patient cannot be NPO or on diuretics prior to test.
Causes for Rejection:Insufficient sweat yield; less than 15 mg for the collection.

Processing and Shipping

Test Performed at or Referral Lab Lab Sendouts  (Sweat Chloride Lab-Discovery Clinic)


Reference Range:


Chloride (mmol/L)

All ages

CF unlikely: Less than 30

Intermediate: 30-59

Indicative of CF: Greater than or equal to 60


Repeat test is recommended when sweat collection weight below 15 mg if results are intermediate or screen and test results do not agree. Patients should be on a low sodium diet for 2 weeks prior to repeat testing.



Use:Establish the diagnosis of cystic fibrosis. The test is useful in the evaluation of malabsorption, pancreatic insufficiency, history of meconium ileus and other problems of gastrointestinal tract, salt depletion syndrome, nasal polyps, aspermia, and chronic or recurrent lung disease, all of which may be symptoms of cystic fibrosis.

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