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Serum or Plasma Sweat Mass Concentration of Sodium

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

This test measures the amount of sodium in sweat, which can help diagnose conditions like cystic fibrosis or other genetic disorders affecting sweat glands.

Quick summary

["Assesses sodium levels in sweat for potential genetic or metabolic disorders."]

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

Key facts at a glance

LOINC
68933-1
Short code
SIgA Sweat-mCnc
Synonyms
SIgA Sweat-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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

Why Is This Test Done?

Your doctor may order this test if you have symptoms like frequent lung infections, thick mucus, or unexplained salt loss. It’s often used to screen for conditions like cystic fibrosis or other sweat gland disorders.

What to Expect Before the Test

You’ll wear a special suit or bandages to collect sweat over 4–8 hours. A trained professional will help ensure accuracy. Avoid sweating excessively (e.g., exercise) before testing.

How the Test Works

Sweat is collected using a patch or bandage, then analyzed in a lab to measure sodium concentration. The test helps determine if your body loses too much salt through sweat.

What the Results Mean

High sodium levels in sweat may indicate conditions like cystic fibrosis or primary aldosteronism. Low levels are less common but could signal other metabolic issues. Results are compared to standard reference ranges.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Sodium Sweat Test

Frequently asked questions

What causes high sodium levels in sweat?
Genetic disorders (e.g., cystic fibrosis), certain medications, or hormonal imbalances may lead to excessive sodium loss in sweat. Rarely, other metabolic or kidney conditions could contribute.
How is sweat collected for this test?
Sweat is collected using a patch or bandage placed on the forearm or back. You’ll wear it for 4–8 hours, and a trained technician will help ensure proper placement to avoid contamination.
Can I eat or drink before the test?
Yes, but avoid excessive sweating (e.g., hot baths, intense exercise) before testing. Eat and drink normally unless instructed otherwise by your doctor.
  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