Leukemia and Hematologic Oncology 2018 - The potential importance of a vitamin B12 assay as a possible early marker in the working diagnosis of malignancy and blood disorders

Hypercobalaminemia (high serum vitamin B12 levels) is a frequent and underestimated anomaly. The most obvious cause of an elevated vitamin B12 level is taking too much of the vitamin in the form of supplements. On the other hand, the etiological profile of high serum cobalamin predominantly encompasses severe disease entities for which early diagnosis is critical for prognosis. These entities are essentially comprised of solid neoplasms, hematological malignancies and liver and kidney disease. Vitamin B12 is generally not considered toxic in high levels, but it’s important to determine if the elevation is due to excess vitamin supplements since other causes of a high vitamin B12 level are usually serious. This review reflects the potential importance of the vitamin B12 assay as an early diagnostic marker of these diseases.