Determination of Folate Vitamers in Human Serum by Stable-Isotope-Dilution Tandem Mass Spectrometry and Comparison with Radioassay and Microbiologic Assay

Abstract
Background: Current clinical methods for folate give different results and cannot measure the various forms of folate. We developed an isotope-dilution tandem mass spectrometric method coupled to liquid chromatography (LC/MS/MS) as a candidate reference method for 5-methyltetrahydrofolic acid (5MeTHF), 5-formyltetrahydrofolic acid (5FoTHF), and folic acid (FA) in human serum.