It was Christmas week 1990 in Oakland. Steven Bloom was wandering through The Lot, that timeless gathering of hippies that springs up in the parking lot before every Grateful Dead concert, when a Deadhead handed him a yellow flyer.
Because of the general safety of the vitamin, upper limits for normal intake do not exist. If your blood values for the vitamin fall below a range of 170 to 250 picograms per milliliter, you may develop a B12 deficiency.
Vitamin B12 Blood Levels Range and Test Results. Normal values of vitamin B12 in blood are between 200 to 900 picograms per milileter. Talk to your lab and request the specific values since every lab values ânormal rangeâ differently.