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Selenium/Creatinine Ratio, 24-Hour Urine

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

Measures urinary selenium relative to creatinine in a 24-hour urine collection to help assess selenium exposure and body stores.

Quick summary

["This test helps evaluate selenium levels, including possible excess exposure or nutritional status."]

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

Key facts at a glance

LOINC
44402-6
Short code
Selenium/Creat 24h Ur-sRto
Synonyms
Selenium/Creat 24h Ur-sRto
Category
kidney
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

What is this test?

This test measures selenium in all urine collected over 24 hours and compares it with the amount of creatinine in the same sample. Creatinine adjustment helps account for differences in urine concentration.

Why might I need this test?

It may be used to assess selenium nutrition, investigate suspected selenium exposure, or monitor certain people who take selenium supplements or have ongoing occupational or environmental exposure.

How is the test performed?

You collect urine in a labeled container for a full 24-hour period according to the laboratory's instructions. The laboratory then measures selenium and creatinine in the collected sample and calculates their ratio.

How do I prepare for the test?

Follow the laboratory's 24-hour urine collection instructions carefully, including the start and end times and any refrigeration requirements. Tell your clinician about selenium supplements and relevant dietary or occupational exposure, and do not change supplement use unless instructed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

24-Hour Urine Selenium/Creatinine Ratio

Frequently asked questions

Why is creatinine included in the result?
Creatinine helps adjust the selenium measurement for urine concentration, making results more comparable across samples. The ratio does not replace interpretation of the complete 24-hour urine collection.
Can selenium supplements affect this test?
Yes. Supplements and foods containing selenium can affect the measured level, so your clinician should review them when interpreting the result.
What if the 24-hour urine collection is incomplete?
An incomplete collection can make the result unreliable. Contact the laboratory for instructions on whether and how to repeat the 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