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Test Code LAB1728 Sweat Test

Important Note

CALL AT LEAST 24 HOURS IN ADVANCE TO PRE-SCHEDULE TEST COLLECTION.

FOR ST LOUIS CHILDREN'S HOSPITAL OUTPATIENT LAB CALL (314) 454-4143

Performing Laboratory

St. Louis Children's Hospital Laboratory - Special Chemistry

Specimen Requirements

Patient Preparation: Specimens collect by SLCH outpatient lab only

Collection Container/Tube:

Preferred/Acceeptable: Lab collect only. Sweat test will be collected into a macroduct collection device by lab.

Submission Container/Tube: May not be received from outside facility

Specimen Collection Volume: minimum of 15 mcl of sweat in a macroduct collection device will need to be collected per site.

Special Instructions: Schedule collection with outpatient lab 

 

Sample Rejection

Mislabled or unlabeled specimens

Logistics

Test Availability: Monday-Friday

Cut-off time (for analysis): 1345

Turnaround Time: Same Day if received before cut-off

Reference Values

Reference Interval: 

All ages:
   Cystic Fibrosis Unlikely: below 30 mmol/L
   Indeterminate: 30-59 mmol/L
   Indicative of Cystic Fibrosis: ≥ 60 mmol/L                                                     
Reference: J. Pediatric 2017; 181S:S4-15.

Critical Value: >or = 30 mmol/L

Every critical result will be called back automatically each time.

Methodology

Titration

Limitations

  • NA

Additional Information

FOR SLCH CORE LABORATORY USE ONLY

Lab Processing Instructions: None. Phlebotomist collecting specimen will deliver specimen vial directly to Special Chme bench

Processed Volume: A minimum of 15 mcl of sweat needs to be collected per site

Analyte Stability:

Specimen Type Temperature    Time     
Sweat (unprocessed)     Ambient NA
  Refrigerated      NA  
  Frozen  NA   

Test Classification and CPT Code

82438 - Chloride BF

89230 - Specimen collection by Iontoph

LOINC

Chloride Sweat: 2077-6

Grams of Sweat: 33247-8

Last Reviewed

07/2025