Sign in →

Test Code Sweat CL Sweat Chloride

Important Note

Call CAMC Women and Children's Outpatient Lab at  304-388-1504 to schedule test.

Performing Laboratory

Women and Children Hospital Laboratory      304-388-2385

Specimen Requirements

Sweat-Macroduct Sweat Collection Device

50 uL (minimum 15uL from each site)

 

The collection and the analysis be performed in duplicate.

A suitable site on the patient’s lower arm or upper leg only, should be selected for the attachment of electrodes for the iotophoresis procedure. The selected site must be free of breaks, fissures, or any other abnormality in the skin. There should be no sign of inflammation, rash, or eczematous lesion, due to the likelihood of contamination by serous fluid. The area must be wrinkle-free and hairless as possible.

Do not attempt iontophoresis on a patient who is receiving oxygen-enriched respiratory therapy in an enclosed space. The possibility of an explosion due to the generation of an electrical spark cannot be discounted. With medical approval, it is often possible to remove the patient form such an environment for the duration of the iontophoresis, perhaps with the temporary support of a respiratory facemask.  

Sweat MUST NOT be stimulated or collected from the head or the trunk. The electrodes used for stimulation must be placed such that iontophoretic current NEVER crosses the patient’s trunk, to avoid the possibility of current crossing the heart, resulting in cardiac depolarization.

Storage and Stability

Not acceptable to refrigerate or freeze specimens

Reference Values

<30 mmol/L Newborns with positive newborn screen; CF unlikely Other population;CF unlikely
30-59 mmol/L All populations; intermediate range Needs further study to rule out CF as a diagnosis
> 60 mmol/L All populations; indicative of CF For individuals presenting with a postive newborn screen or clinical features or family history

Methodology

Stimulation iontophoresis -Collection

Choridometer-Analysis

Days Test Set Up and Turnaround

Monday through Friday, 8:00 AM- 4:00 PM

Results available within 72 hours

CPT Coding

89230-Collection

82438- Analysis

Additional Information

All positve tests must be repeated at a different collection time.  The techologist will notify the patient's physcian and document the date and time the physician was notified of the positive result. 

Use:  The sweat test with iontophoretic stimulation is considered the most reliable single test in the doagnosis of cystic fibrosis. Test becomes positive between 3 and 5 weeks of age in most affected infants.