Cut-off values of vitamin B12 in children

One of the important topics discussed during the B12 conference on 8 & 9 June in Rotterdam is the cut-off values of vit B12 in children. There are no protocols in the diagnostics on this. New protocols are essential because, in the past 20 years, several scientific articles have been published in which healthy children’s average B12, MMA, and homocysteine values have been mapped, which are much higher than in adults. That seems logical because vitamin B12 is also involved in cell division, ergo crucial for growth. Scientists (Paediatricians Dr Anne-Lise Monsen and Dr Ingrid Rours) want to advocate the development of children’s protocols as this does not yet exist. Hopefully, this protocol will prevent permanent health and (brain) damage to children.



  1. Monsen A-LB, Refsum H, Markestad T, Ueland PM. Cobalamin Status and Its Biochemical Markers Methylmalonic Acid and Homocysteine in Different Age Groups from 4 Days to 19 Years. Clinical Chemistry 2003;49(12):2067-2075. (10.1373/clinchem.2003.019869)
  2. van Beynum IM, den Heijer M, Thomas CM, Afman L, Oppenraay-van Emmerzaal D, Blom HJ. Total homocysteine and its predictors in Dutch children. The American Journal of Clinical Nutrition 2005;81(5):1110-1116. (
  3. HOGEVEEN M, BEIJNUM Iv, ROOIJ Av, L. KLUIJTMANS, HEIJER Md, BLOM H. Methylmalonzuurconcentraties bij gezonde Nederlandse kinderen. Ned Tijdschr Klin Chem Labgeneesk 2009;34:3.
  4. Sole-Navais P, Cavalle-Busquets P, Fernandez-Ballart JD, Murphy MM. Early pregnancy B vitamin status, one-carbon metabolism, pregnancy outcome and child development. Biochimie 2016;126:91-6. DOI: 10.1016/j.biochi.2015.12.003.
  5. Sobczyńska-Malefora, A., Katayev, A., Steed, D., O’Logbon, J., Crook,M., & Harrington, D. J. (2023). Age- and ethnicity-related reference intervals for serum vitamin B12Clinical biochemistry111, 66–71.