title: Development of a new standard reference material: SRM 1955 (homocysteine and folate in human serum).
abstract: Total homocysteine (tHCY) and folate are interrelated biomarkers for arteriosclerosis and coronary heart disease. Although many different methods for both tHCY and folate are clinically available, the intermethod and interlaboratory results are often poor, resulting in the need for a matrix reference material and reference methods. The National Institute of Standards and Technology (NIST) has developed isotope dilution liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/ tandem mass spectrometry (LC/MS/MS) methods for determination of tHCY and several folate forms including 5-methyltetrahydrofolic acid (5MT) and folic acid (FA). Additionally, a method for simultaneous measurement of tHCY, 5MT, and FA has been developed and validated. In collaboration with the Centers for Disease Control and Prevention (CDC), mass spectrometric methods and methods used in clinical laboratories have been applied to characterize a new Standard Reference Material (SRM), SRM 1955, "Homocysteine and Folate in Human Serum," containing low, medium, and high levels of tHCY and 5MT. Additionally, FA, 5-formyltetrahydrofolic acid (5FT), vitamin B12, and total folate values are provided. Use of the new SRM should improve clinical measurements and will permit traceability to internationally recognized certified reference materials, as described by European Directive 98/79/EC on in vitro diagnostic medical devices.
authors.affiliation: Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
authors.forename: Mary B
authors.initials: MB
authors.lastname: Satterfield
authors.forename: Lorna T
authors.initials: LT
authors.lastname: Sniegoski
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Sharpless
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Welch
authors.forename: Adriana
authors.initials: A
authors.lastname: Hornikova
authors.forename: Nien-Fan
authors.initials: NF
authors.lastname: Zhang
authors.forename: Christine M
authors.initials: CM
authors.lastname: Pfeiffer
authors.forename: Zia
authors.initials: Z
authors.lastname: Fazili
authors.forename: Mindy
authors.initials: M
authors.lastname: Zhang
authors.forename: Bryant C
authors.initials: BC
authors.lastname: Nelson
mesh_terms: D005492:Folic Acid / Q000097:blood* / Q000737:chemistry; D006710:Homocysteine / Q000097:blood* / Q000737:chemistry; D006801:Humans; D013058:Mass Spectrometry; D015394:Molecular Structure; D012015:Reference Standards; D014481:United States; D014492:United States Public Health Service
chemical_list: D006710:Homocysteine; D005492:Folic Acid