Article

Comparison of serum and red blood cell folate microbiologic assays for national population surveys.

National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA.
Journal of Nutrition (Impact Factor: 4.23). 07/2011; 141(7):1402-9. DOI: 10.3945/jn.111.141515
Source: PubMed

ABSTRACT Three laboratories participated with their laboratory-specific microbiologic growth assays (MA) in the NHANES 2007-2008 to assess whether the distributions of serum (n = 2645) and RBC folate (n = 2613) for the same one-third sample of participants were comparable among laboratories. Laboratory (L) 2 produced the highest and L1 the lowest serum and RBC folate geometric means (nmol/L) in the NHANES sample (serum: L1, 39.5; L2, 59.2; L3, 47.7; and RBC: L1, 1120; L2, 1380; L3, 1380). Each laboratory produced different reference intervals for the central 95% of the population. Pearson correlation coefficients were highest between L3 and L1 (serum, r = 0.95; RBC, r = 0.92) and lowest between L2 and L1 (serum, r = 0.81; RBC, r = 0.65). Notable procedural differences among the laboratories were the Lactobacillus rhamnosus microorganism (L1 and L3: chloramphenicol resistant, L2: wild type) and the calibrator [L1: [6S]5-methyltetrahydrofolate (5-methylTHF), L2: [6R,S] 5-formyltetrahydrofolate ([6R,S] 5-formylTHF), L3: folic acid (FA)]. Compared with 5-methylTHF as calibrator, the folate results were 22-32% higher with FA as calibrator and 8% higher with 5-formylTHF as calibrator, regardless of the matrix (n = 30 serum, n = 28 RBC). The use of different calibrators explained most of the differences in results between L3 and L1 but not between L2 and L1. The use of the wild-type L. rhamnosus by L2 appeared to be the main reason for the differences in results between L2 and the other 2 laboratories. These findings indicate how assay variations influence MA folate results and how those variations can affect population data. To ensure data comparability, better assay harmonization is needed.

0 Bookmarks
 · 
122 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Hispanic women have higher rates of neural tube defects and report lower total folic acid intakes than non-Hispanic white (NHW) women. Total folic acid intake, which is associated with neural tube defect risk reduction, has been found to vary by acculturation factors (i.e. language preference, country of origin, or time spent in the United States) among Hispanic women. It is unknown whether this same association is present for blood folate status. The objective of this research was to assess the differences in serum and red blood cell (RBC) folate concentrations between NHW women and Mexican American (MA) women and among MA women by acculturation factors. Cross-sectional data from the 2001-2010 National Health and Nutrition Examination Survey (NHANES) were used to investigate how blood folate concentrations differ among NHW or MA women of childbearing age. The impact of folic acid supplement use on blood folate concentrations was also examined. MA women with lower acculturation factors had lower serum and RBC folate concentrations compared with NHW women and to their more acculturated MA counterparts. Consuming a folic acid supplement can minimize these disparities, but MA women, especially lower acculturated MA women, were less likely to report using supplements. Public health efforts to increase blood folate concentrations among MA women should consider acculturation factors when identifying appropriate interventions.
    Maternal and Child Nutrition 06/2014; · 2.97 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To determine an optimal population red blood cell (RBC) folate concentration for the prevention of neural tube birth defects.
    BMJ Clinical Research 07/2014; 349:g4554. · 14.09 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Folate is a B-vitamin with particular importance during reproduction due to its role in the synthesis and maintenance of DNA. Folate is well known for its role in preventing neural tube defects (NTDs) during the periconceptional period. There is also an increased need for folate throughout pregnancy to support optimal growth and development of the fetus and blood volume expansion and tissue growth of the mother. During lactation, women are at risk of folate deficiency due to increased demands to accommodate milk folate levels. Nutrient Intake Values (NIVs) for folate have been calculated to take into account additional needs during pregnancy and lactation. However, these values vary widely between countries. For example, the folate requirement that is set to meet the needs of almost all healthy women during pregnancy varies from 300 µg/day in the United Kingdom to 750 µg/day in Mexico. Currently, there is no accepted standardized terminology or framework for establishing NIVs. This article reviews country-specific NIVs for folate during pregnancy and lactation and the basis for setting these reference values.
    Nutrients 10/2013; 5(10):3920-3947. · 3.15 Impact Factor

Full-text

Download
0 Downloads
Available from