Understanding the marker
Selenium is a mineral used by enzymes, including some involved in thyroid hormone processing. Testing can help investigate a specific concern about too little or too much selenium.
The test is interpreted with dietary intake, any supplements and the reason it was ordered. Selenium's role in the body does not mean that everyone benefits from testing or supplements. The blood value alone does not establish a need for supplementation.
What does high Selenium mean?
A high selenium result needs review of possible exposure, including supplements when used. Excess intake can be harmful, but the result alone does not establish the source or degree of exposure.
What does low Selenium mean?
A low concentration may support deficiency in an appropriate clinical context; it does not by itself diagnose a thyroid problem or establish a benefit from supplements.
More markers in the same area
- Vitamin D (25-OH)the blood measure used to assess vitamin D supply
- Vitamin B12needed for nerves and red cells
- Folate (B9)helps your body make new cells
- Vitamin A (Retinol)for vision, immunity, and skin
- Vitamin E (alpha-Tocopherol)a vitamin that helps protect cell membranes
- Holotranscobalaminthe portion of B12 available for cells to take up
This is general information about the marker, not an assessment of your values and not medical advice. Last updated: October 2026.