Selenium in Whole Blood or Urine

Clinical Information

Selenium, an essential trace mineral for humans, is abundant in food. It is a cofactor of enzymes involved in carbohydrate metabolism and gluconeogenesis2. It also plays a crucial role in the normal function of the immune system, thyroid hormone metabolism, and successful reproduction 3. Selenium is also an important antioxidant reducing reactive oxygen species (ROS) to harmless products as water and alcohols4.

Signs and Symptoms of Deficiency or Toxicity

Selenium deficiency is associated with Keshan Disease, Kashin-Beck Disease, or be induced by total parenteral nutrition (TPN)3.

Muscular weakness, muscle wasting, and inflammation and damaged heart muscle have been reportedly observed in patients on TPN without added selenium4. Deforming arthritis may also be present among patients with Kashin-Beck disease3.

Selenium overdose can be toxic. Symptoms observed are hair and nail brittleness and loss, skin rashes, garlic breath odor, fatigue, and irritability4.

Supplementation Guide

No published guidelines for supplementation for the general public. Following are frequently used dosages of supplemental selenium for the prevention of a deficiency7. For adult and teenage males: 40 to 70 mcg/day; Adult and teenage females: 45 to 55 mcg/day; Pregnant females: 65 mcg/day; Breastfeeding females: 75 mcg/day; Children, 7-10 y.o.: 30 mcg; Children, 4-6 y.o.: 20 mcg/day.

Following are the established upper limits for selenium per age group8.

  • For infants:
    • 0-5 months: 45 mcg
    • 6-11 months: 60 mcg
  • For children:
    • 1-3 y.o.: 90 mcg
    • 4-8 y.o.:150 mcg
    • 9-13 y.o.: 280 mcg
    • 14-18 y.o.:400 mcg
  • For adults (19 years and older), pregnant/lactating women: 400 mcg

Selenium can interact with Cisplatin1.

Food Sources

Selenium can be found in crabmeat, salmon, halibut, pasta, pork, shrimp, whole-wheat bread, brown rice, beef, milk, and black walnuts9

(1) Office of Dietary Supplements-National Institutes of Health. (n.d.). Selenium. Fact Sheet for Health Professionals. Retrieved from
(2) Huskisson E, Maggini S, Ruf M. The role of vitamins and mineral in energy metabolism and well-being. The Journal of International Medical Research 2007; 35: 277-289
(3) British Nutrition Foundation. (July 2001). Selenium and Health. Briefing Paper. Retrieved from
(4) Higdon J, Drake VJ, Delage B. (June 2015). Linus Pauling Micronurient Information Center. Selenium. Retrieved from
(5) Mayo Clinic Medical Laboratories. (n.d.). Test Catalog. Selenium, Blood. Retrieved from
(6) Ashton K, Hooper L, Harvey LJ, Hurst R, Casgrain A, Fairweather-Tait SJ. Methods of assessment of selenium status in humans: a systematic review. American Journal of Clinical Nutrition 2009; 89(6):2025S-2039S. doi:10.3945/ajcn.2009.27230F
(7) Micromedex. (n.d.). Drugs and Supplements. Selenium Supplement (Oral Route). Retrieved from
(8) Philippine Dietary Reference Intakes. 2015. Department of Science Technology-Food and Nutrition Research Institute.
(9) Linus Pauling Institute. Oregon State University. (n.d.). Micronutrients for Health. Retrieved from