Excellent 4.6 out of 5
Cardiovascular and Vascular Diseases

Blood Testing for Vitamin B12 Deficiency

Vitamin B12 deficiency impairs red blood cell production and nerve function, leading to anemia and neuropathy. Blood testing confirms status early. Superpower offers Hemoglobin, MCV, MCH, MCHC, RDW, Vitamin B12, and Folate testing, in-clinic or at home. Home testing is available in New York and California.

Book a blood Vitamin B12 Deficiency test
Cancel anytime
HSA/FSA eligible
Results in a week
Physician reviewed

Every result is checked

·
CLIA-certified labs

Federal standard for testing

·
HIPAA compliant

Your data is 100% secure

Key Benefits

  • Confirm or rule out vitamin B12 deficiency with blood counts and vitamin levels.
  • Spot macrocytic anemia early; high MCV/MCH with low hemoglobin flags deficiency.
  • Clarify fatigue, numbness, memory changes potentially caused by low B12.
  • Differentiate B12 versus folate deficiency to target the correct therapy.
  • Guide treatment decisions; results support oral dosing versus injections and duration.
  • Protect fertility and pregnancy; B12 and folate support ovulation and neural development.
  • Track recovery; rising hemoglobin and normalizing RDW confirm response over weeks.
  • Prevent irreversible nerve injury by detecting deficiency before neuropathy progresses.

What are Vitamin B12 Deficiency biomarkers?

Biomarkers for vitamin B12 deficiency tell the story of how well your cells are receiving and using this essential nutrient. Vitamin B12 supports DNA production and nerve insulation, acting as a cofactor in two key reactions (methionine synthase and methylmalonyl‑CoA mutase). Blood testing looks at different points in this pathway. Total vitamin B12 estimates what’s circulating. Holotranscobalamin (active B12) shows how much B12 is actually bound to its carrier and available for delivery to cells. Downstream metabolites—methylmalonic acid (MMA) and homocysteine—reveal whether B12‑dependent reactions are running smoothly inside tissues; when B12 is insufficient, these molecules build up. Together, these markers help confirm true cellular deficiency, catch problems early—often before anemia or nerve symptoms appear—and hint at whether the issue is intake, absorption, or transport (transcobalamin). In short, B12 deficiency biomarkers map supply, delivery, and cellular use, giving a clear, biologically grounded picture of B12 status that a single number cannot.

Why is blood testing for Vitamin B12 Deficiency important?

Vitamin B12 deficiency testing looks at how your body makes DNA, red blood cells, and myelin for nerves. Serum B12 is the core marker, but the complete blood count (hemoglobin, MCV, MCH, MCHC, RDW) and folate give the physiologic context. Together they show whether cells are building properly, oxygen is delivered well, and the nervous system is protected.General reference ranges: hemoglobin tends to be 13.5–17.5 in men and 12–16 in women, with “feels best” usually in the mid-range. MCV about 80–100, MCH 27–33, and MCHC 32–36 typically sit comfortably in the middle; RDW around 11–14.5 is healthiest toward the low end (uniform cell size). Serum B12 is commonly 200–900, with function often most reliable in the mid–upper range. Folate is often 5–20, with adequacy in the mid–upper range.When B12 is low, DNA synthesis slows, producing fewer but larger red cells: hemoglobin drifts down, MCV and MCH rise, MCHC stays normal, and RDW widens. Fatigue, shortness of breath, glossitis, and pale skin reflect anemia, while numbness, tingling, balance problems, mood and memory changes signal impaired myelin. Children and teens may show learning or growth issues; pregnancy increases demand and deficiency raises risks for fetal development even if folate is normal. Folate deficiency can look similar in blood counts, but only B12 lack causes the neuropathy. Very high B12 usually reflects supplements or, rarely, liver or blood disorders; macrocytosis can also come from alcohol, liver disease, hypothyroidism, or medications.Big picture: B12 status links hematologic health, neurocognitive function, and one‑carbon metabolism (homocysteine, methylmalonic pathways). Tracking B12 with CBC indices and folate helps catch reversible problems early, protecting energy, cognition, pregnancy outcomes, and long‑term nerve integrity.

What insights will I get?

Vitamin B12 deficiency blood testing is essential because Vitamin B12 is a cornerstone for healthy energy production, brain function, red blood cell formation, and DNA synthesis. Deficiency can disrupt multiple body systems, leading to fatigue, cognitive changes, nerve problems, and anemia. At Superpower, we assess Vitamin B12 status using a panel of biomarkers: Hemoglobin, MCV (mean corpuscular volume), MCH (mean corpuscular hemoglobin), MCHC (mean corpuscular hemoglobin concentration), RDW (red cell distribution width), Vitamin B12, and Folate.Hemoglobin measures the oxygen-carrying protein in red blood cells. MCV, MCH, and MCHC describe the size and hemoglobin content of red blood cells, while RDW reflects the variation in their size. Vitamin B12 and Folate are vitamins required for red blood cell production and DNA synthesis. In Vitamin B12 deficiency, red blood cells often become larger than normal (macrocytic), and their development is impaired, which is reflected in changes to MCV, MCH, and RDW. Low hemoglobin may indicate anemia, a common consequence of prolonged deficiency. Folate is tested alongside B12 because both are needed for similar cellular processes, and deficiencies can overlap or mask each other.Stable and healthy values in these biomarkers suggest robust red blood cell production and nervous system support. When these markers are out of range, it may signal impaired cell division, reduced oxygen delivery, or neurological vulnerability due to Vitamin B12 deficiency.Interpretation of these results can be influenced by factors such as age, pregnancy, chronic illness, certain medications, and laboratory methods. These variables can affect both the levels and the clinical significance of each biomarker.

Superpower also tests for

See more diseases

Frequently Asked Questions About

What is Vitamin B12 Deficiency blood testing?

This testing checks whether your body has enough B12 to build normal red blood cells and protect nerves. It combines direct levels (Vitamin B12, Folate) with red blood cell indices (Hemoglobin, MCV, MCH, MCHC, RDW) to spot macrocytic, megaloblastic anemia and distinguish B12 from folate problems. Superpower tests your blood for Hemoglobin, MCV, MCH, MCHC, RDW, Vitamin B12, and Folate.

Why should I get Vitamin B12 Deficiency blood testing?

It clarifies causes of fatigue, weakness, memory issues, and numbness by assessing oxygen-carrying capacity and red cell size. It can uncover B12 deficiency, folate deficiency, or mixed patterns, and point to absorption problems such as pernicious anemia. Early detection helps prevent irreversible nerve damage (neuropathy) and tracks bone marrow response to treatment.

Can I get a blood test at home?

Yes. With Superpower, our team member can organise a blood draw in your home.

How often should I test?

Test at baseline if you have symptoms or risk factors. If results are abnormal or you start treatment, recheck after about 8–12 weeks to confirm marrow response and normalization of indices. With ongoing risks (malabsorption, certain medications, gastric surgery), periodic monitoring every 6–12 months is reasonable. More frequent checks may be needed during diagnosed deficiency until stable.

What can affect biomarker levels?

Recent B12 or folate supplements or injections can raise serum levels without fixing functional deficiency. Metformin, proton pump inhibitors, and gastric surgery reduce absorption. Pregnancy dilutes hemoglobin; dehydration concentrates it; smoking can raise it. Alcohol use, liver or thyroid disease, inflammation, and bone marrow disorders alter indices (MCV, RDW). Strict vegan diets lower intake. Hemolysis or lab timing issues can affect results. Folate status can mask or mimic B12 patterns.

Are there any preparations needed before the blood test for Hemoglobin, MCV, MCH, MCHC, RDW, Vitamin B12, Folate?

No fasting is required. Avoid taking high-dose Vitamin B12, folate, or multivitamins the day before the draw if possible, as they can transiently raise serum levels. High-dose biotin can interfere with some immunoassays; pausing for 24–48 hours helps if safe. Stay well hydrated. Take regular medicines as usual unless directed otherwise. Superpower measures Hemoglobin, MCV, MCH, MCHC, RDW, Vitamin B12, and Folate.

Can lifestyle changes affect my biomarker levels?

Yes. Dietary B12 and folate intake influence serum levels within days and red cell indices over weeks as new cells are made. Alcohol can enlarge red cells (raise MCV). Smoking and hydration shift hemoglobin concentration. Weight loss, pregnancy, and chronic illness can change results through volume status and inflammation. These markers reflect nutrient supply, absorption, and bone marrow performance, not just diet on the day of testing.

How do I interpret my results?

Low B12 with low hemoglobin and high MCV points to B12 deficiency causing megaloblastic anemia; RDW often rises as cell sizes vary. Low folate can look similar, so comparing Folate clarifies the cause. MCH rises with macrocytosis; MCHC usually stays normal. Normal indices with low B12 can occur early or with mixed conditions. If B12 is borderline, metabolic markers (methylmalonic acid, homocysteine) better reflect cellular deficiency. Patterns over time show marrow recovery or ongoing deficiency.

How it works

1

Test your whole body

Get a comprehensive blood draw at one of our 3,000+ partner labs or from the comfort of your own home.

2

An Actionable Plan

Easy to understand results & a clear action plan with tailored recommendations on diet, lifestyle changes, supplements and pharmaceuticals.

3

A Connected Ecosystem

You can book additional diagnostics, buy curated supplements for 20% off & pharmaceuticals within your Superpower dashboard.

Superpower tests more than 
100+ biomarkers & common symptoms

Developed by world-class medical professionals

Supported by the world’s top longevity clinicians and MDs.

Dr Anant Vinjamoori

Superpower Chief Longevity Officer, Harvard MD & MBA

A smiling woman wearing a white coat and stethoscope poses for a portrait.

Dr Leigh Erin Connealy

Clinician & Founder of The Centre for New Medicine

Man in a black medical scrub top smiling at the camera.

Dr Abe Malkin

Founder & Medical Director of Concierge MD

Dr Robert Lufkin

UCLA Medical Professor, NYT Bestselling Author

membership

$17

/month
Billed annually at $199
A smartphone displays health app results, showing biomarker summary, superpower score, and biological age details.
A website displays a list of most ordered products including a ring, vitamin spray, and oil.
A smartphone displays health app results, showing biomarker summary, superpower score, and biological age details.A tablet screen shows a shopping website with three most ordered products: a ring, supplement, and skincare oil.
What could cost you $15,000 is $199

Superpower
Membership

Your membership includes one comprehensive blood draw each year, covering 100+ biomarkers in a single collection
One appointment, one draw for your annual panel.
100+ labs tested per year
A personalized plan that evolves with you
Get your biological age and track your health over a lifetime
$
17
/month
billed annually
Flexible payment options
Four credit card logos: HSA/FSA Eligible, American Express, Visa, and Mastercard.
Start testing
Cancel anytime
HSA/FSA eligible
Results in a week
Pricing may vary for members in New York and New Jersey **

Finally, healthcare that looks at the whole you