What it measures
B12 supports nerves and red blood cell production. Low levels are more common with vegan diets, metformin, acid-reducing medicines, weight-loss surgery, and age. Borderline results sometimes need a methylmalonic acid (MMA) test to clarify.
Who should consider it
- People who follow a vegan or mostly plant-based diet
- Adults on metformin or long-term acid reducers
- Anyone with numbness, tingling, memory change, or unexplained anemia
How to read your result
- Under 200 pg/mL is commonly considered low. 200 to 300 pg/mL is a gray zone.
- Symptoms such as numbness or balance trouble need medical attention even with borderline results.
Reference ranges differ between labs. Use the range printed on your own report.
What to do next
A CBC can show whether low B12 has affected your red blood cells.
Where to order Vitamin B12
These sellers include an independent physician order. You pay online and visit a partner lab. Availability, price, and lab network vary, so confirm at checkout.
Private MD Labs
Online lab seller- Says 4,500+ Quest and Labcorp locations
- Every order reviewed by a physician. Says you pay $1 to start and the rest after results.
- Secure online portal with plain-English explanations. Says many results arrive overnight.
HealthLabs
Online lab seller- Says 4,500+ labs, including Quest and Labcorp
- Online or by phone. No doctor referral or insurance needed.
- Secure HealthLabs account. Says 1 to 3 business days.
Walk-In Lab
Online lab seller- Lab network not named on its homepage
- Online, no insurance or doctor order needed. Shows a $6 physician fee per order on popular tests.
- Online account. Turnaround not stated on its homepage.
Quest Health
Lab-run- Quest, 2,000+ locations
- Buy online and book a Quest appointment. An independent provider is involved.
- Online as soon as ready, with an email alert. Provider discussion included at no extra cost.
Seller details come from each seller's own site and can change. Confirm price, lab location, and state availability at checkout.
Questions people ask
Can I fix low B12 with supplements?
Often yes, but the right route (pills, injections) depends on the cause. A clinician can guide that.
Related guides
Complete blood count
Red cells, white cells, hemoglobin, and platelets.
ReadFerritin
Shows your body's iron stores.
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