Vitamin B12 Deficiency Test
Vitamin B12 Deficiency Test is a laboratory test you can order directly. A vitamin B12 deficiency test measures the level of vitamin B12 in your blood. It is ordered when you have symptoms like fatigue, tingling in hands or feet, or when a clinician suspects poor absorption or a diet low in B12.
- Sample type
- blood
- Category
- Vitamin & Mineral
- Turnaround
- 1-3 business days
- Price
- $35
- Referral
- Not required
A vitamin B12 deficiency test measures the level of vitamin B12 in your blood. It is ordered when you have symptoms like fatigue, tingling in hands or feet, or when a clinician suspects poor absorption or a diet low in B12.
What it measures
- Vitamin B12 (cobalamin) — The main measurement of B12 in your blood.
- Folate (folic acid) — Often checked because low folate can cause similar symptoms.
- Methylmalonic acid (MMA) — A substance that rises when B12 is low; helps confirm deficiency.
- Homocysteine — Another marker that can be elevated with low B12.
- Complete blood count (CBC) — Checks for anemia, which can be caused by low B12.
Who it is for
A clinician may order this test if you have symptoms of deficiency, a diet low in animal products, or conditions that affect absorption like celiac disease or gastric surgery.
Preparation
Usually no fasting is required. Tell your clinician about any supplements you take, as they can affect results.
Results and what they mean
Results are reported as numbers with a reference range. Your clinician interprets them along with your symptoms and history. This is general information, not medical advice.
How to order this test
- Choose the test and place a confidential order online.
- Select a certified collection site and pick a time that suits you.
- Have your specimen collected — most draws take only a few minutes.
- Review results in a secure portal, typically within 1–3 days.
Preparation, hours, and pricing vary by site; confirm details directly with the lab before your visit.
Availability by state
Direct-access online ordering for the vitamin b12 deficiency test is available in most states. It is currently unavailable in 6 states:
Everywhere else you can order confidentially and collect your sample at a certified site. Browse by state →
Frequently asked questions
Do I need to fast for this test?
No, fasting is not typically needed.
What can cause low B12?
Common causes include a vegan diet, problems absorbing B12 from food, and certain medications.
How long until I get results?
Most results are ready within 1 to 3 business days.
Can I take B12 supplements before the test?
Supplements can raise your B12 level, so ask your clinician if you should stop them before testing.