5 years ago

Two International Round-Robin Studies Showed Good Comparability of 5-Methyltetrahydrofolate but Poor Comparability of Folic Acid Measured in Serum by Different High-Performance Liquid Chromatography-Tandem Mass Spectrometry Methods.

Pfeiffer CM, Paladugula N, Fazili Z, Sternberg MR
Background: Serum folate methods produce different results. The comparability of HPLC-mass spectrometry (MS)/MS methods is not well documented.Objective: We conducted an international "round-robin" investigation to assess the comparability, precision, and accuracy of serum folate HPLC-MS/MS methods.Methods: The CDC laboratory, 7 laboratories with independently developed methods (group 1), and 6 laboratories with an adapted CDC method (group 2) analyzed folate forms in 6 serum pools and 6 calibrators from the CDC (duplicate analysis over 2 d) and in two 3-level reference materials (duplicate analysis).Results: All laboratories measured 5-methyltetrahydrofolate (5-methylTHF) and folic acid; some measured additional folate forms. The geometric mean (range) concentrations (nanomoles per liter) for 5-methylTHF in the 6 serum pools were 18.3 nmol/L (CDC), 13.8-28.9 nmol/L (group 1), and 16.8-18.6 nmol/L (group 2); for folic acid the concentrations were 3.42 nmol/L (CDC), 1.09-4.74 nmol/L (group 1), and 1.74-2.90 nmol/L (group 2). The median imprecision (CV) for 5-methylTHF was 4.1% (CDC), 4.6-11% (group 1), and 1.7-6.0% (group 2); for folic acid it was 6.9% (CDC), 4.9-20% (group 1), and 3.9-23% (group 2). The mean ± SD (range) recovery of 5-methylTHF spiked into serum was 98% ± 27% (59-138%) for group 1 and 98% ± 10% (82-111%) for group 2; for folic acid it was 93% ± 29% (67-198%) for group 1 and 81% ± 16% (64-102%) for group 2. The mean relative bias for 5-methylTHF compared with the reference material certificate value was 12% (CDC), -24% to 30% (group 1), and -0.6% to 16% (group 2); for folic acid it was 73% (CDC), -47% to 578% (group 1), and -3.3% to 67% (group 2).Conclusions: For 5-methylTHF, group 2 laboratories demonstrated better agreement and precision, less variable spiking recovery, and less bias by using a reference material. Laboratory performance for folic acid was highly variable and needs improvement. Certified reference materials for serum folate forms and total folate are needed to improve method accuracy.

Publisher URL: https://www.ncbi.nlm.nih.gov/pubmed/28768831

DOI: PubMed:28768831

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.