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FER
81641
Clinical Information: Selenium is an essential element. It is a cofactor required to maintain
glutathione peroxidase (GSH-Px) activity, 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. 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, 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 >90 ng/mL is the usual
treatment. Serum monitoring done on a semi-annual basis checks the adequacy of supplementation.
Selenium toxicity has been observed in animals when daily intake exceeds 4 parts per million (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. 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. Urine quantitation is used to assess clearance and in balance studies.
Useful For: Monitoring selenium replacement therapy
Interpretation: The normal daily intake of selenium is 10 to 35 mcg/day, therefore, the usual daily
output should be the same. Daily excretion of 40 mcg/g creatinine
indicates excessive intake. There is no known toxicity to humans due to intake of modest excesses.
Grossly excessive intake (daily output >500 mcg/g creatinine) may have a teratogenic impact. This effect
has been demonstrated in animals.
Reference Values:
> or =16 years: 15-40 mcg/g creatinine
Reference values have not been established for patients that are less than 16 years of age.
Clinical References: 1. Fleming CR, McCall JT, O'Brien JF, et al: Selenium status in patients
receiving home parenteral nutrition. J Parenter Enteral Nutr 1984;8:258-262 2. Chariot P, Bignani O:
Skeletal muscle disorders associated with selenium deficiency in humans. Muscle Nerve 2003
Jun;27(6):662-668 3. Kvicala J, Zamrazil V, Nemecek J, Anke M: Intake of selenium by seniors of South
Bohemia and urine selenium of seniors in the course of a 1-year supplementation by various selenium
species. Tr Element Electro 2008;25:21-24
Semen Analysis
Clinical Information: Semen is composed of spermatozoa suspended in seminal fluid (plasma). The
function of the seminal fluid is to provide nutrition and volume for conveying the spermatozoa to the
endocervical mucus. Male infertility can be affected by a number of causes. Chief among these is a
decrease in the number of viable sperm. Other causes include sperm with abnormal morphology and
abnormalities of the seminal fluid.
Useful For: Determining male fertility status
Interpretation: See Reference Values.
Reference Values:
Appearance: normal
Volume: > or =1.5 mL
pH: > or =7.2
Motile/mL: > or =6.0 x 10(6)
Sperm/mL: > or =15.0 x 10(6)
Motility: > or =40%
Grade: > or =2.5
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