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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.
1 For vitamin B12 deficiency or pernicious anemia: cyanocobalamin doses of 300-10,000 mcg (microgram) daily have been used. 2  However, some evidence suggests that the most effective oral dose is between 647-1032 mcg/day.he recommended dietary allowances (RDAs) of vitamin B12 are: Infants 0-6 months, 0.4 mcg; infants 7-12 months, 0.5 mcg; children 1-3 years, 0.9 mcg; children 4-8 years, 1.2 mcg; children 9-13 years, 1.8 mcg; older children and adults, 2.4 mcg; pregnant women, 2.6 mcg; and breast-feeding women, 2.8 mcg.