Tags: Disease.
Vitamin B12 deficiency or hypocobalaminemia typically features a low blood level of vitamin B12 however functional B12 deficiency can occur at any serum level; with or without anaemia and/or macrocytosis. The deficiency is common to all age groups and is sometimes diagnosed late due to the lack of a gold standard assay and its complex aetiology. Neuropsychiatric symptoms can precede hematologic signs and are often the presenting manifestation of B12 deficiency.
