Article thumbnail

Folate status assessment history: implications for measurement of biomarkers in NHANES12345

By Barry Shane


This article presents a historical perspective on the different methods used to measure folate status in populations and clinical settings. I discuss some of the advantages and limitations of these procedures. For >50 y researchers have used microbiological assay methods to assess folate status in clinical settings and in population-based studies, such as NHANES. Serum and red blood cell folate values obtained with the Lactobacillus casei assay have formed the basis for current ranges and cutoffs for the establishment of folate sufficiency and for the current dietary reference intakes for folate. Over the past 30 y competitive folate protein binding assays, which are available in kit form, have supplanted microbiological assays in many clinical laboratories because of their ease of use. Several NHANES cycles have used these assays. Folate concentrations obtained with these kits are lower than those from microbiological assays and show a wide variation between different protein binding assay kits. This variation has complicated the setting of values for normal ranges of folate status and the comparison of status changes between different NHANES cycles. The recent development of mass spectrometry methods for folate opens up the possibility of measurement of individual folate vitamers such as folic acid. Past experience with microbiological and competitive protein binding assays indicates some of the technical problems that research will need to address before this promise becomes reality

Topics: NHANES Monitoring of Biomarkers of Folate and Vitamin B-12 Status: a Roundtable Review
Publisher: American Society for Nutrition
OAI identifier:
Provided by: PubMed Central

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.

Suggested articles


  1. (1995). A candidate genetic risk factor for vascular disease: a common mutation in methylenetetrahydrofolate reductase.
  2. A common mutation in the methylenetetrahydrofolate reductase gene affects is associated with an accumulation of formylated tetrahydrofolates in red blood cells.
  3. A microbiologic method for detecting folic acid deficiency in man. Clin Chem 1959;5:275–80.
  4. Analysis of folate form distribution by affinity followed by reverse-phase chromatography with electrochemical detection.
  5. Circulating unmetabolized folic acid and 5-methyltetrahydrofolate in relate to anemia, macrocytosis, and cognitive test performance in American seniors.
  6. Determination of folate vitamers in human serum by stable-isotope-dilution tandem mass spectrometry and comparison with radioassay and microbiologic assay.
  7. Dietary reference intakes (DRI) for thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid, biotin, and choline.
  8. (2011). Disease Control and Prevention. Laboratory procedure manual. Analyte: folate/vitamin B12. Matrix: serum and whole blood.
  9. Experimental nutritional folate deficiency in man.
  10. Folate analytical methodology.
  11. Folate assay: a comparison of radio-assay and microbiological methods.
  12. Folate biochemical pathways and their regulation.
  13. Folate chemistry and metabolism.
  14. Folate deficiency. In:
  15. Folic acid binding by serum and milk.
  16. (1989). Folylpolyglutamate synthesis and role in the regulation of one carbon metabolism. Vitam Horm
  17. Growth factors for bacteria X. Additional factors required by certain lactic acid bacteria.
  18. Isolation of an e wLactobacillus casei factor.
  19. Lactobacillus casei microbiological assay of folic acid derivatives in 96-well microtiter plates.
  20. (1972). Lactobacillus casei response to pteroylpolyglutamates. Anal Biochem
  21. Measurement of serum folate levels and serum folic acid binding protein by 3H-PGA radioassay.
  22. (1977). Metabolism of 5-methyltetrahydrofolate by Lactobacillus casei.
  23. (1997). Microbiological assay for serum, plasma, and red cell folate using cryopreserved, microtitre plate method. Methods Enzymol
  24. (1986). Microbiological assay of 5-formyltetrahydrofolic acid and other folates using an automatic 96-well plate reader. Anal Biochem
  25. Pterins and folates in the nutrition of lower organisms.
  26. (1977). Rate limiting steps in folate metabolism by Lactobacillus casei.
  27. Report of a WHO group of experts. World Health Organ Tech Rep Ser 1972;503.
  28. Studies on the response of Lactobacillus casei to different folate monoglutamates.
  29. The determination of erythrocyte folate concentrations using a two-phase ligand binding radioimmunoassay.
  30. The folate binding in milk.
  31. (1976). Transport and utilization of methyltetrahydrofolates by Lactobacillus casei.
  32. Transport of folate compounds into cells.
  33. vitamin B12 and vitamin B6.
  34. Vitamin status and intake as primary determinants of homocysteinemia in an elderly population.
  35. (1998). Whole-blood folate values in subjects with different methylenetetrahydrofolate reductase genotypes: differences between the radioassay and microbiological assays. Clin Chem