Serum or plasma level of **selenium** (mass concentration)

Why Is This Test Done?

Your healthcare provider may order a selenium test to check for deficiencies, especially if you have symptoms like fatigue, weakened immunity, or thyroid issues. It may also be used in research or specialized clinical settings to monitor selenium status in certain conditions.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the blood draw if your test uses a fasting sample. Bring any medications or supplements you take regularly to your appointment.

How the Test Works

A blood sample is taken from a vein in your arm. The sample is sent to a lab where selenium is measured using a specialized analytical technique, often high-performance liquid chromatography (HPLC) or another precise method.

What the Results Mean

Results are reported as a concentration of selenium in the blood (e.g., micrograms per deciliter). While reference ranges vary by lab, low levels may signal deficiency, while very high levels could indicate exposure to selenium supplements or environmental contaminants.