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Normal value ranges for vitamin B12 vary slightly among different laboratories and can range anywhere between 200 to 900 pg/mL. The general consensus is values less than 200 pg/mL constitute a B12 deficiency.ormal value ranges for vitamin B12 vary slightly among different laboratories and can range anywhere between 200 to 900 pg/mL. The general consensus is values less than 200 pg/mL constitute a B12 deficiency.
Blood B12 Level: Not Reliable. A serum B12 (sB12) level below the normal range indicates that B12 levels are becoming depleted. However, as described below, a sB12 level in the normal range does not ensure that B12 levels are healthy.Unfortunately, medical practitioners still use serum B12 to evaluate function, even of vegans.lood B12 Level: Not Reliable. A serum B12 (sB12) level below the normal range indicates that B12 levels are becoming depleted. However, as described below, a sB12 level in the normal range does not ensure that B12 levels are healthy.