Selenium, Serum (SES)

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Test Code: SELEN

Overview
Ordering
Specimen
Performing
Clinical/Interpretive
Contacts
Coding

Synonyms/Keywords

Se (Selenium)

Useful For

Monitoring selenium replacement therapy

Specimen Requirements

Specimen Type	Preferred Container/Tube	Acceptable Container/Tube	Specimen Volume	Specimen Minimum Volume (allows for 1 repeat)	Pediatric Minimum Volume (no repeat)
Serum	6 mL Plain, royal-blue top Vacutainer plastic trace element blood collection tube		0.8 mL	0.2 mL

Collection Processing Instructions

1. Allow the specimen to clot for 30 minutes, then centrifuge the specimen to separate serum from the cellular fraction.

2. Remove the stopper. Carefully pour specimen into metal-free, polypropylene vial, avoid transferring the cellular components of blood. Do not insert a pipette into the serum to accomplish transfer, and do not ream the specimen with a wooden stick to assist with serum transfer.

3. Submit specimen in 7 mL metal-free, screw-capped, polypropylene vial

Additional Information: High concentrations of gadolinium, iodine, and barium are known to interfere with most metals tests. If either gadolinium-, iodine-, or barium-containing contrast media has been administered, a specimen should not be collected for 96 hours.

Specimen Stability Information

Specimen Type	Temperature	Time	Special Container
Serum	Refrigerated (preferred)	28 days	METAL FREE
	Ambient	28 days	METAL FREE
	Frozen	28 days	METAL FREE

Interference

Selenium is quite volatile; therefore, careful specimen collection is necessary to ensure accurate results.

Severe selenium deficiency may contribute to cardiomyopathy.

Performing Laboratory Information

Performing Location	Day(s) Test Performed	Report Available	Methodology/Instrumentation
Mayo Clinic Laboratories	Monday through Saturday	1 to 3 days	Dynamic Reaction Cell-Inductively Coupled Plasma-Mass Spectrometry (DRC-ICP-MS)

Reference Lab

Mayo Clinic Laboratories

Test Information

Selenium is an essential element. It is a cofactor required to maintain activity of glutathione peroxidase (GSH-Px), an enzyme that catalyzes the degradation of organic hydroperoxides. The absence of selenium correlates with loss of GSH-Px activity and is associated with damage to cell membranes due to accumulation of free radicals.

The normal daily dietary intake of selenium is 0.01 parts per million (ppm) to 0.04 ppm, which is similar to the typical content of soil (0.05 ppm) and sea water (0.09 ppm). Selenium is found in many over-the-counter vitamin preparations because its antioxidant activity is thought to be anticarcinogenic. There is no supporting evidence that selenium suppresses cancer.

In humans, cardiac muscle is the most susceptible to selenium deficiency. With cell membrane damage, normal cells are replaced by fibroblasts. This condition is known as cardiomyopathy and is characterized by an enlarged heart whose muscle is largely replaced by fibrous tissue.

In the United States, selenium deficiency is related to use of total parenteral nutrition. This is therapy administered to patients with no functional bowel, such as after surgical removal of the small and large intestine because of cancer, or because of acute inflammatory bowel disease such as Crohn's disease. Selenium supplementation to raise serum concentration >70 ng/mL is the usual treatment. Serum monitoring done on a semiannual basis checks the adequacy of supplementation.

Selenium toxicity has been observed in animals when daily intake exceeds 4 ppm. Teratogenic effects are frequently noted in the offspring of animals living in regions where soil content is high in selenium such as south-central South Dakota and northern-coastal regions of California. Selenium toxicity in humans is not known to be a significant problem except in acute overdose cases. Selenium is not classified as a human teratogen.

Reference Range Information

0-2 months: 45-90 mcg/L

3-6 months: 50-120 mcg/L

7-9 months: 60-120 mcg/L

10-12 months: 70-130 mcg/L

13 months-17 years: 70-150 mcg/L

> or =18 years: 110-165 mcg/L

Interpretation

Selenium accumulates in biological tissue. The normal concentration in adult human blood serum is 110 to 165 mcg/L. Optimal selenium concentration is age dependent (see Reference Values); children require less circulating selenium than adults.

In the state of selenium deficiency associated with loss of glutathione peroxidase activity, the serum concentration is usually below 40 mcg/L.

Outreach CPTs

CPT	Modifier (if needed)	Quantity	Description	Comments
84255