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Chloride, sweat

Item Value
Approval req'd? No
Available Stat? No
Test code SWCL
Test group Chloride
Performed by Mission Bay Chemistry
In House Availability Monday-Friday (day shift)
Method Coulometric Titration (Wescor ChloroChek 3400 Chloridometer)
Patient Preparation Patient is well hydrated the day before and day of testing and dressed warmly at appointment.
Collection Instructions By appointment only: call UCSF Mission Bay Chemistry Lab at 415-476-0183 from 0800-1530 hours, Monday-Friday.
Container type
Amount to Collect See preferred volume
Sample type Sweat
Preferred volume At least 15 µL sweat, collected by Mission Bay lab personnel.
Units mmol/L
Normal range For infants up to and including 6 months of age:
CF unlikely < 30 mmol/L,
Intermediate 30-59 mmol/L,
Indicative of CF ≥ 60 mmol/L.

For individuals older than 6 months of age:
CF unlikely < 40 mmol/L,
Intermediate 40-59 mmol/L,
Indicative of CF ≥ 60 mmol/L.

Reference ranges adopted from:
Farrell PM, et al. Guidelines for diagnosis of cystic fibrosis in newborns through older adults: Cystic Fibrosis Foundation consensus report. J Pediatr 2008;153:S4-S14
Synonyms Cl; Sodium, sweat; Cl-; cystic fibrosis; CF
Turn around times 1-3 days
Additional information Outpatient testing is done in the Gateway Medical Building, 6th Floor Pediatric Pulmonary Clinic, Station 6A. Patients should arrive prior to the scheduled time to allow for registration, and should bring a written request from the ordering physician. Requisitions may be faxed to (415) 476-4863 ahead of time. The test lasts about one hour, during which time the patient should remain near the laboratory to check upon the progress of the test.

The laboratory usually schedules one patient per day. Calls to schedule same-day testing are acceptable but depend on the lab staff availability. A scheduled appointment may be delayed if the laboratory has to provide urgent services to ICN or LDR patients prior to the time of the appointment. Such delays will be notified as soon as possible to the outpatient upon arrival or the inpatient's caregiver (physician or nurse). Sweat chlorides can be performed only between 8 a.m. to 1 p.m., Monday through Friday. When scheduling 1 p.m. appointments, please request unit to remind outpatients to be on time.

Sodium measurement on sweat is not offered.
CPT coding 89230, 82438
LOINC code 2077-6
Last Updated 9/20/2016 11:38:46 AM
Entry Number 189
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