Vitamin B12 Test: What It Shows and What It Does Not
Quick answer: A vitamin B12 test measures the amount of B12 in your blood. B12 is needed for nerves and for making red blood cells. A low level can come from diet, absorption problems or certain medicines.
About this test
The test measures vitamin B12 in your blood. Your body gets B12 from animal foods and supplements and needs a protein in the stomach to absorb it.
Why is it ordered?
- Tiredness, tingling or numbness, memory changes or anemia.
- Checking people at higher risk of low B12, such as those who eat little animal food, are older, have absorption conditions or take metformin or acid reducing medicines.
- Following B12 treatment.
What results may show
- A low level can go along with B12 deficiency.
- A level in the low normal range may need further tests that your provider chooses.
What this test may not show
- It does not show why B12 is low.
- Supplements raise the level and can hide deficiency in a recent sample.
- A result in the normal range does not rule out deficiency in everyone.
- Folate and iron are separate tests.
How to prepare
- Fasting may be requested. Follow the instruction given when you order.
- Tell your provider about B12 supplements, multivitamins and medicines.
Where you can get this test
| Option | Price | Includes |
|---|---|---|
| Vitamin B12 Test | $50 | Vitamin B12 only |
| Anemia Panel | $150 | Ferritin, iron, TIBC, B12, folate and the main blood count markers |
A doctor’s visit is not required to order. Order online, then visit our Buffalo Grove or Lake Zurich location for the sample. Review results with your own healthcare provider.
Related tests
Frequently asked questions
What can cause low B12?
Low intake, trouble absorbing it, and some medicines.
Can folate hide a B12 problem?
High folate intake can improve the blood count while B12 related nerve effects continue, which is why the two are often checked together.
Do B12 supplements change the test?
Yes. Tell your provider what you take.
Sources
Medically reviewed by Rodion Levin, FNP-C, Founder and Medical Director. This page is for general education. It does not diagnose a condition or replace advice from your healthcare provider.
