Medicare Part B covers a vitamin B12 blood test when your doctor orders it to diagnose or monitor a medical condition
Medicare Part B pays for the lab work itself — the blood draw and the test that measures your B12 level — when a doctor writes an order for it. You pay 20% of the Medicare-approved amount after you meet your Part B deductible. The test is usually covered because B12 deficiency causes real medical problems: pernicious anemia, nerve damage, and cognitive changes. Medicare does not cover the test if you order it on your own without a doctor's order, or if you use a direct-to-consumer lab service that does not work through your doctor.
The coverage applies whether you have Original Medicare (Part A and B) or a Medicare Advantage plan, though Advantage plans set their own cost-sharing rules. Some Advantage plans cover the test with no copay; others charge $10 to $50. You should check your plan documents or call the plan before the test to know what you will pay.
Key Takeaways
- Your doctor must order the B12 blood test for Medicare Part B to cover it; self-ordered tests through direct-to-consumer labs are not covered.
- You pay 20% of the Medicare-approved amount after your Part B deductible is met, unless you have a Medicare Advantage plan with different cost-sharing.
- The test is covered when ordered to diagnose or monitor conditions like pernicious anemia, B12 deficiency, or neurological symptoms.
- If your doctor suspects B12 deficiency based on your symptoms or medical history, ask them to order the test rather than ordering one yourself.
When Medicare Part B will pay for the test
Medicare Part B covers the B12 blood test when a doctor orders it as part of diagnosis or treatment. Common reasons include fatigue, weakness, numbness or tingling in the hands or feet, memory problems, or anemia. If you have pernicious anemia (an autoimmune condition that prevents B12 absorption), your doctor may order periodic B12 tests to monitor your levels. Medicare also covers the test if you have had gastrointestinal surgery that affects B12 absorption, or if you take metformin long-term, which can lower B12.
The test code Medicare recognizes is usually CPT 82607 (cyanocobalamin/B12 level). Your doctor's office will use this code when they send the order to the lab. The lab bills Medicare directly, and Medicare processes the claim based on whether the order came from a doctor and whether the reason for testing is medically necessary.
What you pay out of pocket
Under Original Medicare, you pay 20% of the Medicare-approved amount for the lab test after you have met your Part B deductible for the year. The Medicare-approved amount for a B12 blood test is typically $15 to $25, so your 20% share is usually $3 to $5. If you have not yet met your deductible (which was $226 in 2024), you pay the full approved amount until the deductible is satisfied, then 20% after that.
If you have a Medicare Advantage plan, your cost depends on your plan's rules. Some plans cover lab work with no copay when ordered by an in-network doctor. Others charge a flat copay ($10 to $50) or a percentage. A few plans require you to meet a deductible first. Call your plan's customer service number (on the back of your card) before the test to find out your exact cost.
If you use an out-of-network lab or order a test without a doctor's order, Medicare will not pay, and you will owe the full cost — often $50 to $150 depending on the lab.
How to make sure Medicare will cover your test
Start by seeing your primary care doctor or a specialist who knows your medical history. Tell them about your symptoms — fatigue, weakness, numbness, memory problems, or any other concerns. Let them decide whether a B12 test makes sense. Do not order a test from a direct-to-consumer lab service (like Quest or LabCorp's at-home options) without a doctor's order, because Medicare will not pay for those.
Once your doctor decides to order the test, ask them to send it to a lab that accepts Medicare. Most major labs (Quest Diagnostics, LabCorp, your hospital's lab) accept Medicare. Your doctor's office will handle the order and billing. You do not need to do anything except show up for the blood draw and bring your Medicare card.
If you have a Medicare Advantage plan, confirm that the lab is in-network before you go. Your plan's website or customer service line can tell you which labs are covered. Using an out-of-network lab may mean higher costs or no coverage at all.
B12 tests ordered for other reasons
Medicare does not cover B12 testing ordered for reasons that are not medical — for example, to check your B12 level as part of a general "wellness" screening when you have no symptoms and no medical reason to suspect deficiency. Some direct-to-consumer labs market B12 tests as part of a "micronutrient panel" or "anti-aging workup." If you order these without a doctor's medical reason, you pay the full cost yourself.
Similarly, if you are taking B12 supplements on your own and want to check whether they are working, Medicare will not cover a test ordered just to monitor supplement use. However, if your doctor orders a test to monitor B12 levels as part of treating a diagnosed condition (like pernicious anemia or post-surgery), that test is covered.
What happens after the test
The lab sends your results to your doctor, usually within one to three business days. Your doctor reviews the results and contacts you with the findings. If your B12 is low, your doctor may recommend oral supplements, injections, or dietary changes depending on the cause. If you have pernicious anemia, you will likely need regular B12 injections, which Medicare Part B also covers when ordered by a doctor.
Keep a copy of your test results for your records. If you see multiple doctors, share the results with all of them so they know your B12 status. If you need follow-up testing to monitor your levels over time, your doctor can order those tests, and Medicare will cover them the same way.
Frequently Asked Questions
Can I order a B12 blood test on my own without seeing a doctor?
You can order one through a direct-to-consumer lab, but Medicare will not pay for it. You will owe the full cost, usually $50 to $150. Medicare only covers tests ordered by a doctor for a medical reason. If you want Medicare to cover the test, you need to see a doctor first.
Does Medicare cover B12 injections if my test shows I am deficient?
Yes. Medicare Part B covers B12 injections when a doctor orders them to treat B12 deficiency or pernicious anemia. You pay 20% of the approved amount after your deductible. Many people receive injections monthly or every few months depending on their condition.
What if my Medicare Advantage plan denies the B12 test?
Call your plan to ask why. If your doctor ordered it for a medical reason, the plan should cover it. If the plan still refuses, ask your doctor to file an appeal or to contact the plan on your behalf. You can also file a complaint with Medicare if you believe the plan wrongly denied a medically necessary test.
Will Medicare cover a B12 test if I am on dialysis or have kidney disease?
Yes, if your doctor orders it. People with kidney disease and those on dialysis often have B12 issues, and doctors regularly test for it. The test is covered the same way as for anyone else — 20% coinsurance after your deductible under Original Medicare.
Do I need a referral to get a B12 blood test?
No. Your primary care doctor can order the test directly without a referral. If you see a specialist who suspects B12 deficiency, they can order it too. You do not need permission from your insurance plan first.