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Cystic Fibrosis Sweat Conductivity Test

Published: August 9, 2026Updated: August 16, 2026

Measures the conductivity of sweat to help evaluate for cystic fibrosis, particularly when symptoms or family history suggest the condition.

Quick summary

["Abnormally high sweat conductivity may be associated with cystic fibrosis but requires clinical interpretation and sometimes confirmatory testing."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
36834-0
Short code
CTA Ves W contr IV
Synonyms
CTA Ves W contr IV
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ct-angio
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What is this test?

This test measures how well sweat conducts electricity. Sweat conductivity is used as a screening tool for cystic fibrosis and may be followed by sweat chloride or genetic testing when results need confirmation.

Why might I need this test?

It may be ordered for infants or children with symptoms such as repeated lung infections, poor growth, or salty-tasting skin. It may also be used when a parent or sibling has cystic fibrosis or when screening is part of a newborn evaluation.

How is the test performed?

Sweat glands are stimulated, usually with pilocarpine delivered by iontophoresis, and sweat is collected from the skin. The laboratory then measures the sweat's electrical conductivity. If too little sweat is collected, the test may need to be repeated.

How do I prepare for the test?

Follow the testing center's instructions and tell the staff about any medications, skin conditions, or recent illness. Avoid applying lotions, oils, or other products to the testing area unless the clinic specifically directs you to do so.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Cystic fibrosis sweat test

Frequently asked questions

Does this test diagnose cystic fibrosis by itself?
Not always. An elevated result raises suspicion for cystic fibrosis, but the diagnosis may require repeat testing, sweat chloride measurement, genetic testing, and review of symptoms.
Is sweat conductivity the same as a sweat chloride test?
No. Conductivity measures the electrical properties of sweat, while a sweat chloride test measures the chloride concentration. The tests are related but are not interchangeable.
What if not enough sweat is collected?
The result may be difficult or impossible to interpret, and the testing center may ask you to return for another attempt. Proper preparation can help improve sweat collection.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy