Selenium

Clinical Use: To determine deficiency or toxicity of selenium levels.
Background:

Selenium is a trace mineral that is essential to good health but required only in small amounts. Selenium is incorporated into proteins to make selenoproteins, which are important antioxidant enzymes. The antioxidant properties of selenoproteins help prevent cellular damage from free radicals. Free radicals are natural by-products of oxygen metabolism that may contribute to the development of chronic diseases such as cancer and heart disease. Other selenoproteins help regulate thyroid function and play a role in the immune system. Plant foods are the major dietary sources of selenium. The content of selenium in food depends on the selenium content of the soil where plants are grown or animals are raised.

Selenium also can be found in some meats and seafood. Animals that eat grains or plants that were grown in selenium-rich soil have higher levels of selenium in their muscle. Some nuts are also sources of selenium.

There is evidence that selenium deficiency may contribute to development of a form of heart disease, hypothyroidism, and a weakened immune system.

Three specific diseases have been associated with selenium deficiency:

  • Keshan Disease, which results in an enlarged heart and poor heart function, occurs in selenium deficient children.
  • Kashin-Beck Disease, which results in osteoarthropathy.
  • Myxedematous Endemic Cretinism, which results in mental retardation.

Selenium deficiency has also been seen in people who rely on total parenteral nutrition (TPN) as their sole source of nutrition.

Reference Ranges:
  • Up to 7 days old: 0.33 – 0.97µmol/L
  • 7 days to 5 months old: 0.51 – 1.12µmol/L
  • 5 months to 1 year old: 0.60 – 1.29µmol/L
  • 1 year to 14 years old: 0.75 – 1.46µmol/L
  • 14 years old and above: 0.66 – 1.57µmol/L
Associated Diseases:
Patient Preparation: None required
Specimen Requirements: Dark blue topped sodium heparin (trace element tube) specimen required.
Turnaround Time: 2 weeks
Additional Information:
Referred Test: Referred test
Location: Special Biochemistry, Freeman Hospital, Newcastle-upon-Tyne