Vitamin B12 (Cobalamin) Blood Test
Measures total circulating vitamin B12 to help evaluate possible deficiency and interpret supplementation.
- No doctor visit or referral needed
- Members pay our cost on every test, never a markup
- Tracked over time alongside your other results
- HSA/FSA eligible
- Typical results in 1 day · Reviewed by a real clinician
- Drawn at a CLIA/CAP-accredited lab near you · Find labs
Why people order the Vitamin B12 (Cobalamin) Blood Test
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Numbness, tingling, balance changes, or other neurologic symptoms
B12 deficiency can cause neurologic symptoms even without anemia or macrocytosis, but these symptoms are nonspecific and require clinical assessment.
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Unexplained fatigue, weakness, cognitive, mood, or psychiatric changes
These common concerns may justify testing when B12 deficiency is part of the differential diagnosis, but the test should not be presented as a general energy score.
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Macrocytosis, megaloblastic anemia, glossitis, or an unexplained blood-count abnormality
Total B12 can help evaluate compatible blood findings, while a normal blood count does not exclude deficiency.
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Evaluate possible B12 deficiency before starting replacement
An untreated baseline is useful when practical, because tablets, injections, and fortified products can raise the measured concentration.
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Track clinician-directed oral supplementation or nutrition changes
Repeat total B12 may be useful in selected oral treatment plans, but a higher result does not by itself prove that the original cause or symptoms are resolved.
Who may consider the Vitamin B12 (Cobalamin) Blood Test
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A vegan or highly restricted diet without reliable B12 sources
Low intake can reduce B12 stores over time, especially without fortified foods or appropriate supplementation.
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Older age, autoimmune gastritis, celiac disease, or another malabsorption disorder
Reduced absorption can cause deficiency even when dietary intake is adequate. Finding the cause matters because some conditions need lifelong replacement or further evaluation.
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Prior gastric, bariatric, or terminal-ileal surgery
Surgery involving the stomach or terminal ileum can impair the processes needed to absorb vitamin B12.
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Long-term metformin, long-term acid suppression, or recreational nitrous oxide exposure
These exposures can affect B12 absorption, concentration, or function. Suspected nitrous oxide-related deficiency may require MMA or homocysteine rather than relying on total B12 alone.
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Clarify an indeterminate result with functional testing
When symptoms or signs are present and total B12 is indeterminate, serum methylmalonic acid can add functional context.
Should I order total B12 or active B12?
This product measures total serum vitamin B12. Active B12 measures holotranscobalamin and is a different test with different thresholds and intended use. Active B12 may be preferred in selected settings, including pregnancy under current NICE guidance, so confirm the appropriate product when that distinction matters.
Should I add methylmalonic acid if my symptoms persist or my B12 result may be borderline?
It can be useful. Methylmalonic acid adds functional context when total B12 is indeterminate or symptoms remain concerning. It is a separate test and should be interpreted with kidney function and the broader clinical picture.
Do I need to fast or change high-dose biotin before testing?
Follow the selected provider's instructions because fasting requirements differ. Record high-dose biotin and other supplements because they may affect an immunoassay or its interpretation. Do not stop or change supplements or treatment unless a clinician or the order instructions tell you to.
Should I seek care instead of waiting for testing if neurological symptoms are worsening?
Yes. Worsening numbness, weakness, balance problems, cognitive changes, or other concerning neurological symptoms warrant prompt clinical assessment. Do not wait for a routine consumer test or delay treatment simply to preserve a baseline result.
Should I test before starting B12 supplements or receiving a B12 injection?
When practical and safe, obtain the baseline before starting B12 supplements or receiving an injection because recent B12 can raise the measured concentration. Record all B12 tablets and injections, but do not delay urgent evaluation or treatment solely to obtain an untreated baseline.
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What the Vitamin B12 (Cobalamin) Blood Test measures
Measures total circulating vitamin B12 to help evaluate possible deficiency and interpret supplementation.
This is a standalone quantitative total vitamin B12 test, usually performed on serum by immunoassay. Current matched US providers use LOINC 2132-9 and report pg/mL. Some laboratories and guidelines use pmol/L, a different unit that requires conversion, so the result must always display its unit.
Vitamin B12 is needed for DNA synthesis, normal red-blood-cell formation, and neurologic function. Total B12 is a common initial test for suspected deficiency, but it is not a perfect measure of functional B12 status. Symptoms and risk factors matter, and an indeterminate result may need methylmalonic acid, or MMA, testing.
This product is not active B12 or holotranscobalamin, MMA, homocysteine, folate, intrinsic-factor antibody, parietal-cell antibody, or a combined B12 and folate panel. It does not determine the cause of deficiency and should not be represented as a general “energy test.”
- Specimen
- Serum or plasma
- Measures
- Mass concentration
- Reported biomarkers
- Vitamin B12
- Biomarker count
- 1 biomarker
- Fasting
- Special preparation needed (provider-specific fasting)
- Results
- On your Mito dashboard in 1 day, with your range explained
- Reference ranges
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Quest Diagnostics Test 927 selected Labcorp Test 001503 selected
Quest Diagnostics Test 927
- All, Age over 17 years 200-1100 pg/mL
Labcorp Test 001503
- All, No age or sex split published 232-1245 pg/mL
Your results
How to understand your Vitamin B12 (Cobalamin) Blood Test result
This test measures total vitamin B12 circulating in your blood. It is a common first test for possible deficiency, but it does not show perfectly how much B12 is functioning inside cells. Symptoms, risk factors, supplements, injections, and prior treatment all affect how the result should be understood. Do not mix pg/mL and pmol/L values without a validated unit conversion. Always display the source unit.
Low or indeterminate B12
Can support concern about deficiency, although diet, absorption problems, or medicines may contribute. May need methylmalonic acid, a complete blood count, and clinical assessment to clarify an uncertain result.
In range after treatment
Can reflect the effect of supplements or injections even when symptoms or the original cause still need attention. Does not by itself prove that a previous deficiency is fully corrected. Treatment history and clinical response remain important.
Unexpectedly high B12
Is often influenced by supplements or injections and is not proof of toxicity. When it remains high without supplementation, it can be considered alongside the medical history, blood count, liver tests, kidney tests, and other findings.
How much the Vitamin B12 (Cobalamin) Blood Test costs
Compare exact Mito member and non-member prices with recently checked comparable offers. Collection and lab fees are shown separately.
| Lab | Test price | Collection or lab fee |
|---|---|---|
| Mito member | $6.99 | $15.00 Added once per order |
| Mito non-member | $9.79 | $15.00 Added once per order |
| Goodlabs | $10.00 | $12.00 $12 per visit, included in the final checkout total |
| Marek Diagnostics | $19.00 | $10.00 $10 added at checkout for an individual biomarker or custom panel |
| DrSays | $13.99 | $9.99 $9.99 collection fee per order |
| Jason Health | $15.00 | $18.00 $18 lab collection fee per order |
| Ulta Lab Tests | $28.95 | $12.95 $12.95 standard draw fee; some locations may charge more |
| Walk-In Lab | $35.00 | $6.00 $6 per-order physician fee |
Mito prices come from the live catalog for the selected provider. Competitor prices were checked August 22, 2026. Published standalone item price plus the separately disclosed collection or checkout fee.
See the full Vitamin B12 (Cobalamin) Blood Test cost comparison for provider details and comparison notes.
How it works
What to expect from your Vitamin B12 (Cobalamin) Blood Test
- 1 Book instantly
Click, book, done. Choose a convenient lab location near you. Transparent, up-front pricing.
- 2 Quick lab visit
Testing to fit your schedule, usually 15 minutes or less. Walk-in and appointments available. Follow the preparation instructions for your order.
- 3 Results in 1 day
Your result posts straight to your dashboard as soon as the lab completes it.
- 4 Expert guidance
With membership, a clinician reviews your result and a personalized action plan follows, with clear next steps.
Every result comes with a plan
A number on its own does not tell you much. Membership is what turns it into next steps, and keeps track of what changes.
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Insights that connect the dots. A clinician reads your whole picture, not one result in isolation, connecting family history, past results, and lifestyle into clear next steps.
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Your personalized action plan. Nutrition, supplements, and training in one clinician-reviewed protocol, updated as your results change.
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Track your trends. Upload results from any lab and see each biomarker trend over time, so you know what is working.
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Never miss a recheck. Mito tells you what is worth retesting and when, then reminds you so nothing slips.
Vitamin B12 (Cobalamin) Blood Test testing you can trust
Run to clinical-grade standards
- Processed at the same CLIA and CAP-accredited national labs your doctor uses
- Order online, no doctor visit or referral needed
- Your data is encrypted, handled under HIPAA, and never sold
Overseen by our Care Team Lead
Every result, including your Mito Brain analysis, is checked by Rhonda Collins, FNP-C, our Care Team Lead and a board-certified Family Nurse Practitioner with over 15 years of nursing experience across cardiac ICU, primary care, and dermatology.
Meet RhondaEverything your health needs,
in one membership
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Every test at our cost
Members pay our cost on every test, with lab fees passed straight through. The full receipt is itemized, never padded.
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Continuous tracking, all in one place
Upload past labs and watch your trends over time. Every marker and visit lives in one longitudinal record, so all your care stays together.
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Year-round clinician support
Text anytime and get clinician-reviewed answers. When you want to go deeper, 1:1 consultations are available at affordable rates.
Common Vitamin B12 (Cobalamin) Blood Test questions
What does this test measure?
Can deficiency occur without anemia?
What happens if the result is borderline?
Is folate included?
Can supplements make the result look normal or high?
Does a high B12 result mean toxicity?
Do I need to fast?
What if neurologic symptoms are worsening?
Is active B12 the same test?
How do availability and prices vary by state?
Available in all 50 states and Washington, DC.
| States | Provider | Availability | Member price | Non-member price |
|---|---|---|---|---|
| All states and DC except NJ, NY, and RI | Labcorp | Available | $12.22 | $17.11 |
| All states and DC except NJ, NY, and RI | Quest Diagnostics | Available | $6.99 | $9.79 |
| NJ, NY, and RI | BioReference | Available | $13.65 | $19.11 |