Nutrients
Vitamin B12
Unit: pg/mLID: N002
What This Test Measures
Nerve, brain, red blood cell health
Conventional vs. Functional Optimal Range
Conventional "Normal"
232-1245 pg/mLYour doctor says you're "fine" anywhere in this range
Functional Optimal
545-1100 pg/mLThis is where you actually feel great
The gap between these ranges is why you feel terrible with "normal" labs. Conventional medicine waits for disease. Functional medicine optimizes for health.
Gabriel's Take
B12 of 250 pg/mL is "normal" but neurological damage can occur below 400. Gabriel's optimal band is 545-1100. Vegans, elderly, PPI users at risk. Methylcobalamin (not cyanocobalamin) preferred. Low B12 + high homocysteine = functional deficiency even if B12 looks "okay." An unexplained high B12 without supplements deserves a look.
When This Test Is High
Rare (supplementation)
When This Test Is Low
Pernicious anemia, malabsorption, neuropathy, cognitive decline
Related Conditions
Anemia, neuropathy, cognitive impairment, fatigue
Recommended Follow-Up
If low, check MMA, homocysteine; supplement methylcobalamin 1000-5000 μg/day