Laboratory Test Information Guide

Details for Chloride, Sweat

Test Name: Chloride, Sweat
Alternate Name(s): Sweat Chloride
Laboratory: Endocrinology
Specimen Type: See Collection Information.
Collection Information: Special collection. Collected only in Paediatric Medical Day Unit (PMDU) by the Cystic Fibrosis Clinic Nurse. Placing this order does not notify PMDU of this request.

For inpatient requests, please call ext. 52171 for best collection date and time.

For all outpatient requests, please call ext. 78944 or fax request to 519-685-8393.

Please DO NOT send a green Lab or Pulmonary Function requisition.

Sweat Chloride Information Sheet

Map to PMDU-Victoria Hospital
Test Schedule:  
Turnaround time from when specimen
is received in testing laboratory:
2 days
1 day
Reference Range: <30 mmol/L - (negative) Cystic Fibrosis is unlikely
30-59 mmol/L - (indeterminate) Cystic Fibrosis is possible
≥60 mmol/L - (positive) Diagnostic of Cystic Fibrosis
Effective Date: 2008-11-15
Revised Date: 2019-03-27
Critical Value:  
Interpretive Comments: Reliable test in the diagnosis of Cystic Fibrosis. Newborns greater than 36 wk gestation and >2 kg body weight with a positive CF newborn screen, or positive prenatal genetic test, should have sweat chloride testing performed as soon as possible after 10 d of age, ideally by the end of the neonatal period (4 wk of age). Serum electrolytes should be ordered simultaneously to avoid misinterpretation. May be falsely elevated in certain conditions, i.e. malnutrition, edema, diabetes insipidus. Repeat testing is strongly suggested.
Special Processing:  
Method of Analysis: Coulometric titration, using a Chloride Analyzer
Critical Information Required:  
Storage & Shipment:  
System Codes: 
Referred To:  

Questions? Comments? Contact Laura Gopaul