Serum or Plasma Mass Concentration of Vitamin B12 (Cobalamin)
This test measures the amount of vitamin B12 (also called cobalamin) in your blood. Vitamin B12 is essential for nerve function, red blood cell production, and DNA synthesis.
["Vitamin B12 helps prevent serious health issues like anemia and nerve damage."]
Key facts at a glance
- LOINC
- 47412-2
- Short code
- MuV Ab Ser IA-aCnc
- Synonyms
- MuV Ab Ser IA-aCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ia
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your doctor may order this test if you have symptoms like fatigue, weakness, tingling in the hands or feet, or a loss of coordination. It can also be used to check for vitamin B12 deficiency, especially in people with conditions like pernicious anemia, celiac disease, or those who have had gastric surgery. Additionally, it may be part of routine testing for those at higher risk, such as older adults or individuals with poor dietary 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 test, but this depends on the lab’s instructions. Bring any medications you’re taking, as some can affect results. If you’re pregnant, breastfeeding, or have allergies, let your doctor know before the test.
What Happens During the Test?
A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but the process is quick. The blood sample is then sent to a lab for analysis. The test typically takes a few days to return results, depending on lab processing times.
What the Results Mean
Results can help determine if you have a vitamin B12 deficiency or other conditions affecting your blood or nerves. Low levels may indicate poor absorption, dietary deficiencies, or certain medical conditions. High levels might be due to overconsumption or certain genetic conditions.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low vitamin B12 levels can lead to anemia (reduced red blood cells), nerve damage, cognitive issues, or weakness. Early detection and treatment (such as supplements or injections) can prevent serious complications. Your doctor may recommend further tests if results are abnormal, such as checking red blood cell counts or other blood markers.
Short name
Vitamin B12 Level
Frequently asked questions
What causes vitamin B12 deficiency?
How is vitamin B12 deficiency treated?
Can vitamin B12 levels be affected by medications?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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