Whole blood selenium

Whole blood selenium levels can vary between 10 and 3000 ng Se/ml. These levels reflect dietary Intake. With an Se intake of about 50 pg/day, plasma Se levels in humans are about 70 ng/ml, and red blood cell Se is about 90 ng/ml (Levander et a ., 1983). Maximal activity of GSH peroxidase, as determined by assays of the platelet enzyme, is supported where the plasma selenium level is about 100 ng/ml. 

Early animal studies and human population surveys used whole blood as the main indicator of selenium status. Whole blood selenium can be determined after acid digestion using a fluorometric method. The more convenient carbon furnace atomic absorption spectroscopy (CFAAS) assay for plasma and/or serum selenium is now the most widely used procedure. The main components of plasma selenium are extracellular glutathione peroxidase (GSHPx 3) and selenoprotein P. 

No evidence of nail disease was observed in a population living on selenium-rich ranches in the western United States (Longnecker et al. 1991). Doses of selenium were calculated to be between 0.001 and 0.01 mg/kg/day, corresponding to a maximum intake of 0.724 mg/day. Whole blood selenium concentrations were 0.18-0.67 mg/kg. Although these values for the United States are consistent with studies of the Chinese population, only one or a few individuals ingested the highest doses. 

At plasma and whole blood selenium concentrations of <0.10 mg selenium/L, a positive correlation has been reported between blood selenium levels and both erythrocyte and whole blood GSH-Px activity (Perona et al. 1977 Thomson 1977 Valentine et al. 1988). GSH-Px is an enzyme that acts as a scavenger of peroxides and protects cells from oxidative damage. However, whole blood selenium levels... 

Biomarkers of Deficiency. Two endemic diseases, Keshan disease and Kashin-Beck disease, have been reported in selenium-deficient populations in China in which mean hair, blood, and urine selenium levels are low (Yang et al. 1988). Keshan disease, manifested as nausea, vomiting of yellowish fluid, and necrosis of the myocardium, has been found in a population with an average whole blood selenium concentration of 0.018 mg selenium/L, an average urinary concentration of 0.007 mg selenium/L, and an... 

The mean whole blood selenium concentration of residents from 19 U.S. cities ranged from 0.10 to 0.34 mg/L with a mean value of 0.21 mg/L (Barceloux 1999). A synopsis of selenium concentrations in human tissues has been summarized in Table 3-6. 

Clausen J, Nielsen SA. 1988. Comparison of whole blood selenium values and erythrocyte glutathione peroxidase activities of normal individuals on supplementation with selenate, selenite, L-selenomethionine, and high selenium yeast. Biol Trace Elem Res 15 125-138. 

Bi-xia, H., Han-Chang, Z., Gui-gang, Pu, Fang, Y., Shen-chun, Z. and Hong, Y. (1985). Differential pulse cathodic stripping voltammetry of whole blood selenium and serum selenium. Anal. Lett. 18, 279. 

On a normal diet, whole-blood selenium levels range from 0.1 to 0.2 mg/L. One patient with chronic intoxication after ingestion of 31 mg/day had a whole-blood selenium level of 0.53 mg/L. 

The selenium levels of blood and blood components are widely used as indicators of Se status in humans, since they are sensitive to dietary intake and can therefore complement such studies and give an indication of amounts absorbed fixim the diet. A significant correlation was found between dietary Se intake and whole-blood selenium [57]. 

The concentrations of selenium in whole blood and in plasma and/or serum are related to dietary intake. About 50% to 60% of the total plasma selenium is present as the protein selenoprotein P, a highly basic protein having multiple histidine residues and about 10 atoms of selenium per molecule, Around 30% of plasma selenium is present as glutathione peroxidase (GSHPx-3) and the remainder is incorporated into albumin as selenomethionine. ... 

The reference interval for selenium in whole blood, plasma or serum, hair, and nails should be established locally, since these indices are affected by dietary selenium intake. Plasma selenium adult values lie in the interval 63 to 160pg/L (0.8 to 2.0pmol/L). Values of less than 40 pg Se per L (0.5pmoI/L) indicate probable selenium depletion. 

In vitro studies of human plasma and whole blood incubated with sodium selenite have indicated that selenite is accumulated in erythrocytes by an active transport mechanism (Lee et al. 1969). Several studies indicate that the selenite is chemically altered in the erythrocyte and then transported back into the plasma, where the selenium metabolite binds to plasma proteins (Burk 1974 Hirooka and Galambos 1966a Lee et al. 1969). 

Jaakkola K, Tummavuori J, Pirinen A, et al. 1983. Selenium levels in whole blood of Finnish volunteers before and during organic and inorganic selenium supplementation. Scand J Clin Lab Invest 1983 473-476. 

Thomson CD, Rea HM, Doesburg VM, et al. 1977. Selenium concentrations and glutathione peroxidase activities in whole blood of New Zealand residents. Br J Nutr 37 457-460. 

AiEGEEfA A, Baebeea R, Faeee R, Feeeee E, LagaedaMJ and Torres MA (1998) Optimization of selenium determination in human milk and whole blood hy flow injection hydride atomic absorption spectrometry. AOAC Int 81 457-461. 

A similar procedure, evaluated for the determination of selenium in body fluids by hydride / S, has been successfully used for arsenic as well. The flasks are the same as already described above with a long neck and 40 mL volume. However, flasks of similar design (e.g. Kjeldahl flasks) may be used as well. The procedure is as follows. 0.5 mL serum, whole blood or urine is placed into the digestion flasks. If necessary a sample volume of 1.0 ml may be also used. After this 1 mL of nitric acid (65% w/v) is added, the digestion flask placed into the aluminium heating block, and the block slowly heated to 140 °C. This temperature is maintained for 25 min and then cooled to room temperature. 0.5 mL (96% w/v) sulphuric and 0.2 mL (70% w/v) perchloric acid is added to the cool solution. The subsequent programme consists of slowly heating (approx. 15 min) to... 

This chapter will focus on the determination of total selenium in clinical materials, especially body fluids such as whole blood, serum and urine. It is not the purpose to... 

Prepare appropriate standards using animal/human whole blood and serum containing low levels of selenium. 

N ve, J., Thomassen, Y. and van Damme, M. (1992). Cooperative study on the measurement of concentrations of selenium in freeze-dried (human whole) blood. Pure Appl. Chem., 64(5), 765. 

The widespread presence of selenium in food and water and its selective absorption are illustrated by the selenium content of human blood. Allaway, Kubota, Losee, and Roth (43) found an average of 0.2 ppm selenium (20.6 /xgrams Se/100 ml) in whole blood in 210 samples from 19 cities in 16 States in the United States. The selenium contents of these blood samples were within the narrow range of 0.1-0.34 ppm. These values for human blood are 1000-fold that found in river waters (30) and 2000-fold the average selenium in seawater (33). 

Welz and Schubert-Jacobs [7] determined selenium in standard reference whole blood samples (Seronorm 904, 905, 906) by FI-HGAAS using the prototype of a commercialized FI system, FlAS-200, and obtained good agreement with certified values. The performance of the FI procedure was compared to a standard lUPAC batch procedure to show the advantages of the former. 

A. Specific levels are not generally available. Selenium can be measured in the blood, hair, and urine. Whole-blood levels remain elevated longer than serum levels (which are typically 40-60% lower) and may reflect long-term exposure. 

Both whole-blood and urinary concentrations reflect dietary intake. Overexposure should be considered when blood selenium levels exceed 0.4 mg/L or urinary excretion exceeds 600-1000 mcg/day. 

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