title: Biomarkers of folate status in NHANES: a roundtable summary.
abstract: A roundtable to discuss the measurement of folate status biomarkers in NHANES took place in July 2010. NHANES has measured serum folate since 1974 and red blood cell (RBC) folate since 1978 with the use of several different measurement procedures. Data on serum 5-methyltetrahydrofolate (5MTHF) and folic acid (FA) concentrations in persons aged ≥60 y are available in NHANES 1999-2002. The roundtable reviewed data that showed that folate concentrations from the Bio-Rad Quantaphase II procedure (Bio-Rad Laboratories, Hercules, CA; used in NHANES 1991-1994 and NHANES 1999-2006) were, on average, 29% lower for serum and 45% lower for RBC than were those from the microbiological assay (MA), which was used in NHANES 2007-2010. Roundtable experts agreed that these differences required a data adjustment for time-trend analyses. The roundtable reviewed the possible use of an isotope-dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) measurement procedure for future NHANES and agreed that the close agreement between the MA and LC-MS/MS results for serum folate supported conversion to the LC-MS/MS procedure. However, for RBC folate, the MA gave 25% higher concentrations than did the LC-MS/MS procedure. The roundtable agreed that the use of the LC-MS/MS procedure to measure RBC folate is premature at this time. The roundtable reviewed the reference materials available or under development at the National Institute of Standards and Technology and recognized the challenges related to, and the scientific need for, these materials. They noted the need for a commutability study for the available reference materials for serum 5MTHF and FA.
authors: Office of Dietary Supplements, National Institutes of Health, Bethesda, MD 20892, USA. beth@yetley.com
authors: Elizabeth A
authors: EA
authors: Yetley
authors: Christine M
authors: CM
authors: Pfeiffer
authors: Karen W
authors: KW
authors: Phinney
authors: Zia
authors: Z
authors: Fazili
authors: David A
authors: DA
authors: Lacher
authors: Regan L
authors: RL
authors: Bailey
authors: Sheena
authors: S
authors: Blackmore
authors: Jay L
authors: JL
authors: Bock
authors: Lawrence C
authors: LC
authors: Brody
authors: Ralph
authors: R
authors: Carmel
authors: L Randy
authors: LR
authors: Curtin
authors: Ramón A
authors: RA
authors: Durazo-Arvizu
authors: John H
authors: JH
authors: Eckfeldt
authors: Ralph
authors: R
authors: Green
authors: Jesse F
authors: JF
authors: Gregory
authors: Andrew N
authors: AN
authors: Hoofnagle
authors: Donald W
authors: DW
authors: Jacobsen
authors: Paul F
authors: PF
authors: Jacques
authors: Anne M
authors: AM
authors: Molloy
authors: Joseph
authors: J
authors: Massaro
authors: James L
authors: JL
authors: Mills
authors: Ebba
authors: E
authors: Nexo
authors: Jeanne I
authors: JI
authors: Rader
authors: Jacob
authors: J
authors: Selhub
authors: Christopher
authors: C
authors: Sempos
authors: Barry
authors: B
authors: Shane
authors: Sally
authors: S
authors: Stabler
authors: Patrick
authors: P
authors: Stover
authors: Tsunenobu
authors: T
authors: Tamura
authors: Alison
authors: A
authors: Tedstone
authors: Susan J
authors: SJ
authors: Thorpe
authors: Paul M
authors: PM
authors: Coates
authors: Clifford L
authors: CL
authors: Johnson
authors: Mary Frances
authors: MF
authors: Picciano
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