Standard Reference Material (SRM) 2378 fatty acids in frozen human serum. Certification of a clinical SRM based on endogenous supplementation of polyunsaturated fatty acids
Dietary fatty acids can be both beneficial and detrimental to human health depending on the degree and type of saturation. Healthcare providers and research scientists monitor the fatty acid content of human plasma and serum as an indicator of health status and diet. In addition, both the Centers for Disease Control & Prevention (CDC) and the National Institutes of Health – Office of Dietary Supplements are interested in circulating fatty acids (FAs) because they may be predictive of coronary heart disease. The National Institute of Standards and Technology (NIST) provides a wide variety of reference materials (RMs) and Standard Reference Materials® (SRM®s) including blood, serum, plasma, and urine with values assigned for analytes of clinical interest. NIST SRM 2378 Fatty Acids in Frozen Human Serum was introduced in 2015 to help validate methods used for the analysis of FAs in serum, and consists of three different pools of serum acquired from (1) healthy donors who had taken fish oil dietary supplements (at least 1000 mg per day) for at least one month (level 1 material), (2) healthy donors who had taken flaxseed oil dietary supplements (at least 1000 mg per day) for at least one month (level 2 material), and (3) healthy donors eating “normal” diets who had not taken dietary supplements containing fish or plant oils (level 3 material). The use of dietary supplements by donors provided SRMs with natural endogenous ranges of FAs at concentrations observed in human populations. Results from analyses using two methods at NIST, including one involving a novel microwave-assisted acid hydrolysis procedure, and one at the CDC are presented here. These results and their respective uncertainties were combined to yield certified values with expanded uncertainties for 12 FAs and reference values with expanded uncertainties for an additional 18 FAs.
KeywordsHuman serum Fatty acids Supplementation Gas Chromatography/Mass Spectrometry Gas Chromatography- Flame Ionization Detection
Partial financial support for the development and certification of SRM 2378 Fatty Acids in Frozen Human Serum was provided by the National Institutes of Health, Office of Dietary Supplements (NIH-ODS), with guidance from Joseph M. Betz (NIH-ODS) and Stephen A. Wise (NIST).
Compliance with ethical standards
The contractor who collected, processed, and packaged SRM 2378 was required to submit documentation to NIST of their relationship with an appropriate Institutional Review Board (IRB) registered with the US Department of Health and Human Services’ Office of Human Research Protections and located within the community in which the human subject research was conducted. The contractor also had to submit documentation for NIST institutional review and approval. The donors to SRM 2378 signed a form acknowledging that they had read information describing what their blood would be used for, that they had received answers to any questions, and that they gave consent for their blood to be pooled and used in the preparation of a serum SRM.
Certain commercial equipment, instruments, or materials are identified in this report to specify adequately the experimental procedure. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the materials or equipment are the best available for the purpose. The findings and conclusions of the article are those of the authors and do not necessarily represent the official views or positions of the CDC/Agency for Toxic Substance and Disease Registry, the Department of Health and Human Services, or NIST.
Conflict of interest
This work represents no known conflicts of interest with respect to the authors or their institutions.
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