From the Guidelines
High vitamin B12 levels (1400 pg/ml) without supplementation could be caused by several medical conditions, with liver disease, certain blood disorders, and kidney disease being potential underlying causes. The patient's elevated B12 levels may be related to the liver's storage and release of B12, as liver disease can lead to an increase in B12 levels [ 1 ]. Additionally, certain blood disorders like myeloproliferative neoplasms, polycythemia vera, or chronic myelogenous leukemia can also elevate B12 levels. Kidney disease may contribute to high B12 levels by reducing its excretion. Other potential causes include solid tumors, genetic disorders affecting B12 transport proteins, and excessive consumption of B12-rich foods.
Some studies have investigated the relationship between vitamin B12 and other nutrients, such as folate, and their potential impact on health outcomes [ 1 ]. However, these studies do not directly address the cause of high vitamin B12 levels. The patient should consult with their healthcare provider for appropriate testing, which may include:
- Liver function tests
- Complete blood count
- Kidney function assessment
- Possibly imaging studies to identify the underlying cause. While high B12 itself isn't harmful, identifying the underlying condition is important for proper treatment, as it may be associated with other health risks, such as hyperhomocysteinaemia, which has been linked to age-related neurodegenerative disease and decline in physical function [ 1 ].
From the Research
Possible Causes of High Vitamin B12 Levels
- Solid neoplasia (primary or metastatic) and acute or chronic hematological diseases 2
- Liver disorders, monoclonal gammapathy of undetermined significance, renal failure 2
- Inflammatory or autoimmune diseases, and transient hematological disorders (neutrophilia and secondary eosinophilia) 2
- Myeloproliferative disorders, which can mask actual vitamin B12 deficiency despite elevated serum levels 3
Association with Mortality and Length of Stay
- Elevated plasma vitamin B12 concentrations (>1000 pg/mL) are associated with in-hospital mortality in adult patients at nutritional risk 4
- High vitamin B12 levels are also linked to a longer length of stay in the hospital 4