Sweat Chloride Test
A simple, painless test that measures the amount of chloride in your sweat to help diagnose cystic fibrosis, a genetic condition affecting the lungs and digestive system. This safe procedure works for all ages, including newborns, and results are typically available within 1-2 days.
{"The test collects a small sample of sweat, usually from the forearm or thigh","Normal chloride levels are below 30 mmol/L","Elevated levels (60 mmol/L or higher) may indicate cystic fibrosis","The test is safe, painless, and suitable for infants as young as 2 days old","A repeat test is often recommended to confirm abnormal results"}
Key facts at a glance
- LOINC
- 105200-0
- Short code
- CLSWEAT
- Synonyms
- Chloride Sweat Ql Scn
- Category
- electrolyte
- Sample
- serum
- Container
- Specialized sweat collection apparatus (Macroduct or Pilogel patches) with electrodes for iontophoresis
- Units
- not specified
- Ref low
- 30
- Ref high
- 59
- Critical range
- — – 60 not specified
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- screen
- CPT
- 89290
- SNOMED
- 313295005
- Specimen volume
- Minimum 75 mg of sweat (approximately 15-20 μL)
- Stability
- Analyze within 24-48 hours; store at 2-8°C if delay exceeds 4 hours
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
What is this test?
The sweat chloride test measures the amount of chloride (a salt) in your sweat. Chloride is part of the electrolyte balance in your body, and this test helps doctors determine if you have cystic fibrosis (CF), a genetic condition that affects the lungs and digestive system.
How is the test performed?
A small area of skin (usually on the arm or leg) is cleaned and stimulated to produce sweat using a mild electrical current or a special medication. The sweat is collected on a filter paper or in a coiled tube. The sample is then sent to a laboratory for analysis. The entire procedure takes about 30-60 minutes.
Does it hurt?
The test is generally well-tolerated and not painful. You may feel a mild tingling or warmth during the stimulation process, but this is usually minimal. The test is safe for people of all ages, including newborns.
How do I prepare for the test?
No special preparation is needed. You can eat and drink normally before the test. However, you should avoid applying creams, lotions, or oils to the test area for 24 hours before your appointment. Wear loose, comfortable clothing that allows easy access to your arm or leg.
Reference range
Negativenot specified
No fasting required; ensure adequate hydration; avoid applying lotions, creams, or oils to skin collection site for 24 hours prior
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings2
Frequently asked questions
How long does it take to get results?
Can the test be done on babies?
What happens if my results are abnormal?
Is the test covered by insurance?
Sources
- 1
- 2
- 3MedlinePlus - Sweat TestSource
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.
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