Selenium Blood Test in California

A selenium blood test measures the amount of selenium in your blood. Selenium is a mineral that supports thyroid function, immune health, and antioxidant defenses. The test is ordered when a deficiency or excess is suspected, or to monitor supplementation.

What it measures

Selenium (total) — The main mineral level in your blood, reported in micrograms per liter (mcg/L).
Selenium (plasma or serum) — The liquid part of blood, often used for routine testing.
Selenium (whole blood) — Measures selenium inside red blood cells, reflecting longer-term levels.
Glutathione peroxidase (optional) — An enzyme that depends on selenium; sometimes checked with selenium.

Who it is for

A clinician may order this test if you have symptoms of deficiency (such as fatigue or muscle weakness) or excess (such as hair loss or nail changes), or if you are on long-term selenium supplements or intravenous nutrition.

Preparation

No fasting is usually required. Tell your clinician about all supplements, especially selenium, and any medications you take.

Results and what they mean

Results are reported as a number with a reference range, typically in mcg/L. Your clinician interprets the result along with your symptoms, diet, and other tests. This is general information, not medical advice; only a qualified professional can diagnose or treat a condition.

Requesting the Selenium Blood Test in California

Order online, choose a certified collection site in California, and review results through a secure portal. No referral is required, and orders are processed confidentially. Access across Pacific is uneven, so confirming a site ahead of time is worthwhile.

Frequently asked questions

Do I need to fast for a selenium blood test?

No, fasting is not required. You can eat and drink normally before the test.

What can affect my selenium level?

Diet (especially Brazil nuts and seafood), supplements, and certain medical conditions can affect your level.

Is this test covered by insurance?

Coverage depends on your insurance plan and the reason for testing. Check with your insurer or the lab.

How soon will I get results?

Most results are ready within 1–3 business days. Your clinician will discuss what they mean for you.

Selenium Blood Test by city in California

All testing in California → Full Selenium Blood Test guide →