vitamin B12 measurement (EFO_0004620) is is a quantification of Vitamin B12, vitamin B12 or vitamin B-12, is a water-solublevitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood. It is one of the eight B vitamins. It is normally involved in themetabolism of every cell of the human body, especially affecting DNA synthesis and regulation, but also fatty acid synthesis and energy production. It is the largest and most structurally complicated vitamin and can be produced industrially only through bacterial fermentation-synthesis. Also known as: vitamin B12 levels.