ReviewNutrients2024
Macro-B12 and Unexpectedly High Levels of Plasma B12: A Critical Review.
Review in Nutrients, 2024. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 11 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
11 citing papers in PubMed, 7 citations in OpenAlex.
- Vitamin B12 in early childhood: a phenotype-guided approach to deficiency and unexpectedly elevated concentrations.European journal of pediatrics · 2026Review
- Article
- [Pathophysiology of hypervitaminosis B12: from origin to clinical event. Scoping review].Revista medica del Instituto Mexicano del Seguro Social · 2026Article
- B vitamins and cardiovascular health: mechanisms, clinical evidence, and precision prevention strategies.Nutrition & metabolism · 2026Review
- Diagnostic challenge of high vitamin B12 levels: a case report and review of the literature.Journal of medical case reports · 2026Review
- Autoimmune gastritis: a comprehensive review of pathophysiology, risk stratification, and management.Frontiers in immunology · 2026Review
- Diagnosis and treatment of vitamin B12 deficiency in children.Frontiers in nutrition · 2026Review
- Vitamin B12 in Cancer Patients: Clinical Insights into Deficiency, Excess, Diagnosis, and Management.Nutrients · 2025Review
- Elevated serum vitamin B12 concentrations in a patient with pancreatic exocrine insufficiency.Biomarkers in medicine · 2025Article
- Cobalamin Status Among Patients with Fetal Alcohol Spectrum Disorder (FASD)-A Preliminary Study.Nutrients · 2025Article
- Optical bio/chemical sensors for vitamin BBeilstein journal of nanotechnology · 2025Review
Corrections and comments
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Authors and funding
2 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
A low total plasma vitamin B12 supports a clinical suspicion of B12 deficiency, while the interpretation of an unexpectedly normal/high level is marred by controversies. Here, we critically review current knowledge on B12 in blood plasma, including the presence of the so-called "macro-B12". The latter form is most often defined as the fraction of B12 that can be removed by precipitation with polyethylene glycol (PEG), a nonspecific procedure that also removes protein polymers and antibody-bound analytes. Plasma B12 includes B12 attached to transcobalamin and haptocorrin, and an increased concentration of one or both proteins almost always causes an elevation of B12. The total plasma B12 is measured by automated competitive binding assays, often incorrectly referred to as immunoassays, since the binding protein is intrinsic factor and not an antibody. An unexpectedly high level of B12 may be further explored using immunological measurements of haptocorrin and transcobalamin (optionally combined with e.g., size-exclusion chromatography). Nonspecific methods, such as PEG precipitation, are likely to give misleading results and cannot be recommended. Currently, the need for evaluation of a high B12 of unknown etiology is limited since other tests (such as measurements of methylmalonic acid) may better guide the diagnosis of B12 deficiency.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.