Clinical follow-up of children with high vitamin B12 values: should we worry?

Abstract

Vitamin B12 (cobalamin, Cbl) is one of the most important vitamins that can be dissolved in water. It is absorbed in terminal ileum, transported by haptocorrins and stored in the liver. It is involved in methyl transfer and nucleotide synthesis. In children, deficiency leads to megaloblastic anemia and affects neurologic development. The importance of deficiency in children is well understood. There are many studies about vitamin B12 deficiency. [1][2][3] The widespread use of autoanalysers in hospital laboratories has made vitamin B12 testing, like many tests, widespread, inexpensive, fast and accessible everywhere. Thus, all doctors, especially pediatricians, internist and neurologists, have started to request vitamin B12 tests from every patient in which the deficiency might have an impact or relation. Important data have accumulated in laboratory recording systems due to the increased requests. Analysis of these data showed that a significant proportion of the vitamin B12 tests were higher than normal. 1-3 Thus, a new research area related to vitamin B12 levels was opened. The new questions are what is the meaning of this high vitamin B12 (hCbl) level found incidentally high in a patient and how to manage such a patient. These questions are very important, because the high levels of Cbl are seen in malign or proliferative diseases of myeloid and lymphoid

Prevalence of neoplasia and concurrent diseases in dogs and cats with hypercobalaminemia: A retrospective case–control study

“…A limitation of our study was the short follow-up period, which was approximately 1 year in dogs and <2 years in cats, although previous human, cohort-based, retrospective studies identified an association between elevated cobalamin and the development of cancer within a year, 12 hence a 1 year follow up in animals may have been sufficient to observe any effect of hypercobalaminemia on cancer risk. An association between hypercobalaminemia and the development of cancer in children was not observed in previous studies, 13 and although some young animals were included in the present study, only two control dogs and one hypercobalaminemic cat were aged less than 6 months.…”

Challenges in the diagnosis of hypervitaminemia B12. Interference by immunocomplexes

“…However, unexpected high concentrations are sometimes found in these patients [1]. In the literature, hypervitaminemia B12 (hB12) is considered a relatively common finding, between 7-20% [2], even more than its deficiency. However, despite its prevalence, hB12 is a clearly underestimated analytical abnormality [3].…”

“…The aims of our study were [1] to characterize the type of interference in our vitamin B12 immunoassay, [2] to propose an algorithm for the screening of antibody-mediated analytical interferences, and [3] to evaluate the economic impact of the implementation of such an algorithm.…”