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24-Hour Urine Selenium Mass Concentration

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

This test measures the total amount of selenium, a trace mineral, in your urine over a 24-hour period. Selenium helps protect cells from damage and supports immune function.

Quick summary

["Assesses selenium levels in your body through urine, useful for monitoring selenium status over time."]

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

Key facts at a glance

LOINC
47976-6
Short code
Selenium 24h Ur-mCnc
Synonyms
Selenium 24h Ur-mCnc
Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms or conditions linked to selenium deficiency, such as fatigue, hair loss, or weakened immunity. It may also be used to monitor selenium levels in people with certain genetic disorders or those taking selenium supplements.

What to Expect Before the Test

No special preparation is needed. Collect all urine produced in a 24-hour period (from one morning to the next morning) in a clean container. Drink plenty of water to ensure full urine collection.

What Happens During the Test

Your collected urine sample is sent to a lab for analysis. The lab measures the total selenium content using a specialized technique, such as mass spectrometry.

What the Results Mean

Results help determine if your body is getting enough selenium. Abnormal results may prompt further evaluation of dietary intake, absorption, or underlying health conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Selenium is an essential micronutrient that plays a role in antioxidant defense, thyroid function, and immune response. Low levels may contribute to health issues like fatigue, muscle weakness, or increased susceptibility to infections. High levels can sometimes indicate excessive intake or certain metabolic conditions.

Short name

24-Hour Selenium Urine Test

Frequently asked questions

What causes a 24-hour urine selenium test to be recommended?
Your doctor may suggest this test if you have symptoms of selenium deficiency, such as hair loss, muscle pain, or frequent illnesses, or if you have a condition that affects selenium metabolism.
How is the test different from a blood selenium test?
This test measures selenium in urine over 24 hours, giving a more comprehensive picture of your body’s selenium excretion and absorption. A blood test measures selenium levels at a single point in time.
Can dietary changes affect the test results?
Yes, selenium intake from food and supplements can influence urine levels. To avoid interference, avoid taking high-dose selenium supplements for at least a few days before testing.
  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