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Protocol - Selenium

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Description:

The analytical method for serum selenium (Se) is based on inductively coupled plasma mass spectrometry (ICP-MS) using matrix-matched calibration standards. In this method, Se (isotope mass 78 and/or mass 80), and gallium (mass 69) are measured in serum by inductively coupled plasma dynamic reaction cell spectrometry using methane as reaction gas.

Another analytical method to quantify serum selenium (Se) is based on electrothermal atomic absorption (AA), which is commonly used to measure plasma Se and is more accessible for most researchers than ICP-MS. ICP-MS is required for Se-speciation and limited sample cases such as biopsies.

Protocol:

1. Specimen Collection, Storage, and Handling Procedures; Criteria for Specimen Rejection

A. Specimen should be collected in a Red-Top tube that is prescreened for trace metal contamination. Specimen-type serum, optimal amount of specimen required is 2-3 mL, minimum volume required for analysis is about 0.8 mL.

B. Specimens may reach and maintain ambient temperature during analysis. Stringent precautions should be taken to avoid external contamination by the metals to be determined.

C. The criteria for unacceptable specimens are either a low volume (<0.8 mL) or suspected contamination due to improper collection procedures or collection devices. In all cases, a second specimen should be requested.

D. Specimen characteristics that may compromise test results include contamination of serum by contact with dust, dirt, etc. from improper handling.

E. In general, handle specimens in ways that prevent microbial growth. Serum specimens should be transported and stored at 4°C. Once received, they can be frozen at -20°C or at -70°C until time for analysis. Portions of the sample that remain after analytical aliquots are withdrawn and should be refrozen at -20°C. Samples thawed and refrozen several times are not compromised. Dried blood spots are also suitable.

2. Detection Ranges Reference Ranges (Normal Values) adapted from National Committee for Clinical Laboratory Standards (NCCLS) 38A(3): Selenium

Age

µg/L

µmol/L

Preterm

35-94

0.44-1.19

Full Term

57-96

0.72-1.21

1-5 years

96-144

1.22-1.82

6-9 years

101-162

1.28-2.05

10-16 years

103-186

1.31-2.35

Adult

109-181

1.38-2.29

Protocol Name from Source:

2004 National Center for Environmental Health Laboratory Procedure Manual for Serum Selenium

Availability:

Publicly available

Personnel and Training Required

Must complete safety training seminars prior to performing any work in the Lead Poisoning/Trace Elements Laboratory.

Equipment Needs

Highly specialized equipment is necessary to perform accurate selenium measurements.

Requirements
Requirement CategoryRequired
Major equipment Yes
Specialized training No
Specialized requirements for biospecimen collection No
Average time of greater than 15 minutes in an unaffected individual No
Mode of Administration

Bioassay

Life Stage:

Infant, Toddler, Child, Adolescent, Adult, Senior, Pregnancy

Participants:

All ages

Specific Instructions:

Strict adherence to quality control (QC) procedures outlined in the protocol text is recommended. Controls should be run at the beginning of the day, one control should be analyzed again after approximately each of 10 patient samples, and all QC controls are run at the end of each day. Agreement with certified or accepted QC values should be within the ±2 standard deviation limits.

Selection Rationale

This assay is sensitive enough to be used to rapidly screen serum specimens from subjects for elements of toxic and nutritional interest. The protocol is taken from the standard procedure used by the Centers for Disease Control and Prevention (CDC) Elemental Analysis Laboratory for the National Health Examination Survey (NHANES).

Language

English

Standards
StandardNameIDSource
Common Data Elements (CDE) Person Serum Selenium Level Number 2946951 CDE Browser
Logical Observation Identifiers Names and Codes (LOINC) PhenX - selenium protocol 62287-8 LOINC
Process and Review

The Expert Review Panel #1 reviewed the measures in the Anthropometrics, Diabetes, Physical Activity and Physical Fitness, and Nutrition and Dietary Supplements domains.

Guidance from the ERP includes:

• No significant changes to measure

Back-compatible: no changes to Data Dictionary

Previous version in Toolkit archive (link)

Source

Centers for Disease Control and Prevention, Division of Laboratory Sciences, National Center for Environmental Health Laboratory Procedure Manual for Serum Selenium, August 24, 2004.

Lockitch, G., Fassett, J. D., Gerson, B., Nixon, D. E., Parsons, P. J., & Savory, J. (1997). Control of pre-analytical variation in trace element determinations; Approved guideline (NCCLS document C38-A). Wayne, PA: National Committee for Clinical Laboratory Standards.

General References

Centers for Disease Control and Prevention, National Center for Health Statistics. National Health and Nutrition Examination Survey (NHANES) Overview 2007-2008.

Combs, G., Jr., & Gray, W. P. (1998). Chemo preventive agents: Selenium. Pharmacology and Therapeutics, 79, 179-192.

Jackson, I and Combs, GF. (2012) Selenium as a Cancer Preventive Agent in Selenium, Its Molecular Biology and Role in Human Health. Dolph L. Hatfield, Marla J. Berry, Vadim N. Gladyshev, Editors. Springer, New York pp 313-319.

McKenzie, R. C., Rafferty, T. S., & Beckett, G. J. (1998). Selenium: An essential element for immune function. Immunology Today, 19, 342-345.

Office of Dietary Supplements, National Institutes of Health Dietary Supplement Fact Sheet: Selenium.

Thomson, C. D. (2004). Assessment of requirements for selenium and adequacy of selenium status: A review. European Journal of Clinical Nutrition, 58, 391-402.

Protocol ID:

50901

Variables:
Export Variables
Variable NameVariable IDVariable DescriptionVersiondbGaP Mapping
PX050901_Selenium_Collection_MicrogramsPerLiter PX050901010100 Selenium Concentration in ug/L 4 N/A
PX050901_Selenium_Collection_MicroMolar PX050901010200 Selenium Concentration in umol/L 4 N/A
Research Domain Information
Measure Name:

Selenium

Release Date:

October 1, 2015

Definition

A measure to assess concentration (micrograms per liter or micromoles per liter) of serum selenium.

Purpose

Selenium (Se) is important for antioxidant capacity and has cancer prevention properties.

Keywords

Nutrition and Dietary Supplements, antioxidant, NHANES, NCCLS