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Serum Selenium Concentration (Mass Concentration)

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

This test measures the amount of selenium, a mineral important for your health, in your blood serum. Selenium helps protect cells from damage and supports immune function.

Quick summary

["Selenium levels help assess your body’s nutrient status and potential deficiencies."]

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

Key facts at a glance

LOINC
61533-6
Short code
Years selenium PhenX
Synonyms
Years selenium PhenX
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
phenx
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 This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like fatigue, muscle weakness, or immune issues, or if you have conditions like selenium deficiency or certain genetic disorders. It may also be part of routine check-ups for patients with chronic illnesses or those on certain medications that affect nutrient absorption.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a broader metabolic panel. Bring any medications or supplements you’re taking to your appointment.

How the Test Works

A small blood sample is drawn from a vein in your arm. The serum portion is then analyzed to measure selenium concentration using a specialized laboratory technique.

What the Results Mean

Results are compared to general reference ranges for selenium in blood serum. Low levels may indicate deficiency, while very high levels could signal potential toxicity or other underlying conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Selenium Level

Frequently asked questions

What causes selenium levels to be checked?
Your doctor might order this test if you have symptoms like persistent fatigue, muscle weakness, or immune problems, or if you live in an area with selenium-deficient soil. It may also be part of a broader evaluation for conditions like selenium deficiency or genetic disorders affecting nutrient metabolism.
What do low selenium levels mean?
Low selenium levels may suggest a deficiency, which can affect your energy, immune system, or thyroid function. Your doctor may recommend dietary changes, supplements, or further testing to address it.
Can selenium levels be affected by medications?
Yes, certain medications (like some antibiotics or chemotherapy drugs) or supplements (like iron or zinc) can influence selenium levels. Always inform your healthcare provider about all medications or supplements you’re taking.
  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