Vitamin B12 Level of 230 pg/mL: Significance and Treatment
A Vitamin B12 level of 230 pg/mL represents metabolic B12 deficiency and warrants treatment, as this falls below the critical threshold of 258 pmol/L (approximately 350 pg/mL) where functional deficiency occurs even with "normal" laboratory ranges. 1, 2
Understanding This Level
Your B12 level of 230 pg/mL is concerning for several reasons:
- This level falls in the "gray zone" where standard laboratory reference ranges may report it as "normal," but metabolic deficiency is highly likely 2, 3
- Serum B12 <258 pmol/L (~350 pg/mL) with elevated homocysteine or methylmalonic acid (MMA) defines metabolic B12 deficiency, which affects 10.6% of patients overall and 18.1% of those over 80 years 1, 2
- Up to 50% of patients with "normal" serum B12 have metabolic deficiency when measured by more sensitive markers like MMA 2
- The UK NDNS defines deficiency as <150 pmol/L (~203 pg/mL), making your level of 230 pg/mL clearly deficient by this standard 2
Critical Next Steps for Diagnosis
You need additional testing to confirm functional deficiency:
- Measure methylmalonic acid (MMA) - this is the most sensitive marker of functional B12 status and should be checked when B12 levels are indeterminate 1, 2, 3
- Measure homocysteine levels - elevated levels suggest functional deficiency and increased stroke risk (target <10 µmol/L optimal) 1
- Check complete blood count for megaloblastic anemia, though this may be absent in one-third of cases 2
- Consider active B12 (holotranscobalamin) if available - this measures biologically active B12 and is more sensitive than total B12 2, 4
Recommended Treatment Approach
Start oral vitamin B12 supplementation at 1000-2000 mcg daily, which is as effective as intramuscular administration for most patients and costs less 2, 5, 6
Treatment Algorithm:
For patients WITHOUT severe neurologic symptoms:
- Oral B12: 1000-2000 mcg daily until levels normalize, then maintenance therapy 2, 5
- Continue until B12 levels are >350 pg/mL and MMA/homocysteine normalize 2
- Monthly maintenance dosing after normalization 2
For patients WITH severe neurologic manifestations:
- Intramuscular B12: 100 mcg daily for 6-7 days 7
- Then 100 mcg on alternate days for seven doses 7
- Then every 3-4 days for 2-3 weeks 7
- Followed by 100 mcg monthly for life 7
- Use methylcobalamin or hydroxycobalamin instead of cyanocobalamin when possible 1
Why This Matters for Your Health
Neurologic symptoms often present BEFORE hematologic changes and can become irreversible if untreated:
- Cognitive difficulties, memory problems, concentration issues 2
- Peripheral neuropathy 2, 5
- Fatigue 2
- Glossitis or oral symptoms 2
- Depression, brain fog, ataxia 3
Cardiovascular implications:
- B12 deficiency increases stroke risk through elevated homocysteine 1
- B vitamins including B12 reduced ischemic stroke by 43% in meta-analyses 1
- Among stroke patients, 17.3% had biochemical or metabolic B12 deficiency 1
Common Pitfalls to Avoid
Do not rely solely on serum B12 to rule out deficiency, especially if you are over 60 years old, where metabolic deficiency is common despite "normal" serum levels 2
Check for underlying causes:
- Medications: metformin (>4 months use), proton pump inhibitors (>12 months), H2 blockers, colchicine 2, 5, 3
- Autoimmune conditions: test for intrinsic factor antibodies and gastric parietal cell antibodies 3
- Helicobacter pylori testing for atrophic gastritis 3
- Dietary factors: vegetarian/vegan diet 2, 5
- History of gastrointestinal surgery 5, 3
Special Considerations
If you are over 60 years old: You have significantly higher rates of metabolic deficiency (18.1% in those >80 years) despite "normal" serum B12 2, 4
If you have cardiovascular disease or stroke history: Treatment is particularly important as B12 deficiency increases stroke risk, and supplementation can reduce this risk 1
Duration of treatment: Continue until levels normalize, then lifelong maintenance therapy if intrinsic factor antibodies are positive or if you have pernicious anemia 2, 7