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Vitamin B12 (Cobalamin) with Serum Concentration Measurement

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of vitamin B12 in your blood. Vitamin B12 is essential for nerve function, red blood cell production, and DNA synthesis.

Quick summary

["Vitamin B12 helps prevent serious health issues like anemia and nerve damage."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
16827-8
Short code
EBV VCA IgG CSF Ql
Synonyms
EBV VCA IgG CSF Ql
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms like fatigue, weakness, numbness, or tingling in your hands and feet. It could also be done if you have conditions like pernicious anemia, gastrointestinal disorders, or if you follow a strict vegetarian or vegan diet that may limit vitamin B12 intake.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for a few hours before the blood draw, but this depends on your doctor’s instructions. Bring any medications you’re currently taking.

What Happens During the Test

A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but it’s generally quick and painless. The blood sample will be sent to a lab for analysis.

What the Results Mean

Low levels of vitamin B12 can indicate deficiencies, which may require treatment such as injections, oral supplements, or dietary changes. High levels may not always indicate a problem unless they’re significantly elevated and unexplained.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Vitamin B12 Level

Frequently asked questions

What are the normal reference ranges for this test?
Reference ranges can vary by lab and individual health. Your doctor will interpret your results in the context of your overall health and symptoms. If your results are low, you may need further testing or treatment to address potential deficiencies.
How long does it take to get my results?
Results are typically available within a few days to a week, depending on your lab and healthcare provider. Follow-up with your doctor to discuss your results and any next steps.
Can I eat or drink anything before this test?
Check with your doctor or the lab for specific instructions, but generally, fasting may be required for 8–12 hours before the test. Avoid caffeine or alcohol before the blood draw if advised by your doctor.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy