What is this test?
Selenium is a trace element used by antioxidant and thyroid-related enzymes. Both deficiency and excessive supplementation can be harmful.
Why might it be ordered?
- To investigate suspected deficiency or excess in a suitable dietary or medical context.
- To monitor replacement when a clinician has identified a need.
What sample is needed?
A blood sample is required. The laboratory chooses the correct tube and handles the sample for this test.
How should you prepare?
Report supplements and doses and follow the trace-element collection instructions. Do not take extra selenium solely because of an isolated result.
How should you understand the result?
The result depends on the specimen and method and should be compared with the laboratory interval. Symptoms of deficiency or toxicity are nonspecific.
Sources and editorial status
This patient-facing text is an editorial draft. It should be approved by a laboratory physician before official publication.