The selenium test is a direct blood measure of selenium in serum or plasma, which tracks recent intake and the selenoproteins that carry it. Practitioners use it for clients with thyroid concerns, restrictive diets, malabsorption or long-term supplement use, where excess matters as much as deficiency. Inflammation lowers serum selenium and sample types are not interchangeable, so match the result to the lab's range.
| Test type | Measured in a blood sample |
|---|---|
| Measurements required | Selenium only |
| Sample and collection | Blood draw at a collection centre |
| Preparation | No fasting is needed for this test. |
| Turnaround | About 5 to 10 business days |
| Available through | Vitamins & Trace Elements. Available in: Essential Nutrients Test. |
| Pricing | Price on sign-up |
| Results | Returned in the Vively practitioner platform, beside your client's other markers |
What are the Selenium reference and optimal ranges?
| Typical lab reference | Vively optimal | |
|---|---|---|
| Adults | 1.1 to 2.5 µmol/L | 1.5 to 2.5 µmol/L |
Labs differ, and serum, plasma and whole blood results are not interchangeable, so read the result against the range printed on the client's report (RCPA guidance). The optimal range is a target for review, not a diagnostic cut-off.
Check a client's Selenium result
Enter the value from your client's lab report to see where it sits against the typical lab range and the Vively optimal range.
A guide only, not a diagnosis. One result is a starting point: read it with symptoms, history and a repeat test. Labs differ, so check the result against the range on your client's report. Nothing you enter is stored or sent.
How do you arrange Selenium testing through Vively?
- Get verified. Practitioners with a recognised qualification or membership (ATMS, NHAA, ANTA, Dietitians Australia, NSA, CMA or Ahpra registration) can request free practitioner access.
- Choose a panel. Log in to the practitioner platform and pick a panel that includes Selenium, or build your own. Add-on pricing shows when you sign up.
- Client collects. Your client collects at a partner collection centre, with their request on their phone or printed.
- Review results. Results come back to you in the practitioner platform, beside your client's other markers, ready for the follow-up consult.
Which Vively panels include Selenium?
Log in to the practitioner platform to view a panel in full, or build and save your own from 100+ tests and panels.
- Essential Nutrients Test12 markers · NutrientsPrice on sign-upSeleniumVitamin DVitamin B12Red blood cell folateRed Blood Cell MagnesiumRed Blood Cell ZincRed Blood Cell CopperCaeruloplasmin+4 moreLog in to view this panel
Why does the optimal range sit there?
Our 1.5 µmol/L floor sits above the 1.1 µmol/L lab limit, at the point where selenoprotein P plateaus and supply stops limiting synthesis.
In a controlled trial (Hurst et al., American Journal of Clinical Nutrition, 2010), selenoprotein P plateaued at plasma selenium of roughly 120 to 125 µg/L, about 1.5 µmol/L. Above that, extra selenium adds no selenoprotein activity.
Rayman (Lancet, 2012) argued that people already near this level should not take supplements, because higher intake has been linked with type 2 diabetes in trials such as NPC (Stranges et al., 2007).
A client at 2.2 µmol/L who takes selenium has no reason to take more.
What should Selenium be read with?
- LowLow selenium with raised hs-CRP
Inflammation lowers serum selenium, so repeat once CRP settles before reading it as low intake.
- LowLow selenium with high TSH or low free T3
Sometimes seen alongside reduced T4 to T3 conversion; the thyroid results need GP review in their own right.
- LowLow selenium with low albumin and low zinc
Points towards low protein intake or malabsorption.
- ContextSelenium above 2.5 µmol/L
Usually reflects supplements or heavy Brazil nut intake; review every source.
- HighHigh-normal selenium with rising HbA1c or fasting glucose
Trials link selenium supplementation in replete people with type 2 diabetes risk; review whether the supplement is needed.
What can affect a Selenium result?
- Inflammation, infection and recent surgery lower serum selenium
- Sample type: serum, plasma and whole blood selenium have different ranges
- Brazil nuts vary widely in selenium content, so a daily habit can push levels high
- Supplements, including multivitamins and thyroid formulas, raise results
- Low albumin and protein malnutrition lower results
When should you refer the client to their GP?
- Above the lab range, or any level with hair or nail loss, brittle nails, garlic-smelling breath, skin rash or neurological symptoms (possible selenosis)
- Well below the lab range with muscle weakness or heart symptoms, or in clients on long-term parenteral nutrition or after bariatric surgery
- Abnormal TSH or known thyroid disease: thyroid management sits with the GP whatever the selenium result
- Malabsorption (coeliac disease, IBD) with low selenium
How should a client prepare for a Selenium test?
Copy or print this to send to your client.
Preparing for your Selenium test
- No fasting is needed for this test.
- Tell your practitioner if you take selenium, a multivitamin or a thyroid support formula, as many contain selenium.
- Mention if you eat Brazil nuts regularly, as even a few can contain a lot of selenium.
- Take your pathology request to any of 4,000+ collection centres. Bring it printed or on your phone.
- Keep taking prescribed medicines as usual unless your doctor tells you otherwise.
- Results usually take about 5 to 10 business days and come to your practitioner. Book your results appointment for after that.
How do practitioners use Selenium with clients?
Check every product the client takes before reading a high result, as selenium turns up in many multivitamins and thyroid support formulas. In clients with Hashimoto's, trial evidence for selenium lowering thyroid antibodies is mixed, so share the result with their GP or endocrinologist before any change.
Selenium FAQs
Can a naturopath, nutritionist or dietitian order a selenium test through Vively?
Yes. Add it to any client panel on the Vively practitioner platform. It sits in Vitamins & Trace Elements and is also in Essential Nutrients Test. Add-on pricing shows when you sign up. No account yet? Request free access.
Should I check selenium before recommending it for thyroid support?
Yes. Selenium status varies with diet and with soil where food is grown, and a client who is already replete gains nothing from more while carrying some risk. Test first, read the result with TSH and free T4, and involve the client's GP or endocrinologist in any thyroid-directed plan. Recheck if supplementation continues long term.
Do Brazil nuts affect the selenium result?
Yes, often more than clients expect. Selenium content varies many-fold between nuts depending on where they were grown, so a daily habit can lift serum selenium into the upper range or above. Ask how many the client eats and how often. If the result is high, pausing regular Brazil nuts and other sources comes before any retest.
Why does inflammation matter when reading a selenium result?
Inflammation, infection and recent surgery lower serum selenium, so a low value may not reflect low intake. Low albumin and protein malnutrition lower it too. Check hs-CRP on the same draw and repeat once it settles before reading the result as low intake, and consider low protein intake or malabsorption if albumin and zinc are also low.
How do I read a selenium result in the upper half of the optimal range in a client who supplements?
Selenoprotein P plateaus at about 1.5 µmol/L, the bottom of Vively's optimal range of 1.5 to 2.5 µmol/L, so a client at 2.2 µmol/L gains no extra selenoprotein activity from more selenium. More selenium is not better in a replete client. Review every source, including multivitamins and Brazil nuts, and share the result with the client's GP.
References
- Royal College of Pathologists of Australasia. RCPA Manual: Selenium.
- Rayman MP. Selenium and human health. Lancet. 2012.
- Hurst R, Armah CN, Dainty JR, et al. Establishing optimal selenium status: results of a randomized, double-blind, placebo-controlled trial. American Journal of Clinical Nutrition. 2010.
- Stranges S, Marshall JR, Natarajan R, et al. Effects of long-term selenium supplementation on the incidence of type 2 diabetes: a randomized trial. Annals of Internal Medicine. 2007.