Vitamin B12 (Serum or Plasma Mass Concentration)
This test measures the amount of vitamin B12, an essential nutrient needed for healthy nerve function and red blood cell production, in your blood.
["Vitamin B12 helps prevent nerve damage and supports energy levels."]
Key facts at a glance
- LOINC
- 1888-7
- Short code
- Vit B12a SerPl-mCnc
- Synonyms
- Vit B12a SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 200
- Ref high
- 900
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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 This Test Might Be Ordered
Your doctor may recommend this test if you have symptoms like fatigue, numbness, tingling in the hands or feet, weakness, or a history of poor appetite, weight loss, or digestive issues. It may also be checked if you have conditions like pernicious anemia, certain gastrointestinal disorders, or if you’re taking medications that can interfere with vitamin B12 absorption.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast for a few hours before the blood draw if instructed by your healthcare provider. Bring any medications you’re currently taking, as some can affect results.
How the Test Works
A small sample of blood is taken from a vein in your arm. The blood is then analyzed in a lab to measure the concentration of vitamin B12. The test is typically done using a sensitive method to detect very small amounts of the vitamin.
What the Results Mean
Results are compared to a reference range, which can vary slightly by lab. Low levels may indicate vitamin B12 deficiency, while higher levels may require further evaluation to rule out other conditions.
Reference range
NCBI: Vitamin B12 200-900 pg/mLN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low vitamin B12 levels can lead to serious health issues, including anemia (reduced red blood cells), nerve damage, and cognitive problems. Early detection and treatment can prevent long-term complications. High levels may sometimes suggest conditions like vitamin B12 toxicity (rare) or other metabolic disorders that need further investigation.
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 17, 2026. · Read our editorial policy