A low B12 or folate level in a person with signs and symptoms indicates that the person has a deficiency but does not necessarily reflect a medical condition. Some causes of low B12 include:

- Dietary deficiencies (although this is rare in America due to our fortified food products, vegans can experience issues as most B12 dense foods are animal products)

- Malabsorption in the small intestine due to

    - Pernicious anemia

    - Celiac disease

    - Inflammatory bowel disease

- Heavy drinking / chronic alcoholism

- Certain medications

- Pregnancy, all women need increased B12 and folate for proper fetal development

The most common cause of high B12 in the blood is due to recent ingestion or injection of supplemental vitamin B12. It could also be possibly from your diet if high in animal products such as meat, eggs, and shellfish. 

Limited observational studies have reported associations of increased vitamin B12 levels with other conditions and disease states, including:

- Liver disease due to release of B12 from damaged liver cells into the bloodstream

- Kidney disease due to impaired function of the kidneys to excrete excess B12

- Increased levels of transcobalamin, which is a transporter of B12 in the bloodstream

- Inflammatory conditions: rheumatoid arthritis, lupus

- Hematologic (or blood) cancers: acute leukemia, multiple myeloma

- Hematopoietic disorder: myeloproliferative neoplasm, myelodysplastic syndrome, hypereosinophilic syndrome, transient neutrophilia

Most of the medical conditions often present with other abnormal lab findings such as impaired kidney function, liver function, anemia, low white blood cell count and also other signs and symptoms of problems.

If higher levels of B12 persist, it may be worthwhile seeing a hematologist for a follow up evaluation to receive further review of your history, family history and further laboratory testing if appropriate, especially if the levels continue to be high.

Additional note: Please consult your doctor before making any changes in your diet or supplement regimen. You might want to avoid supplements high in B12 for now, eat a varied healthy diet rich in fruits and vegetables and check to see if B12 is in any supplements you take.