Vitamin B12 (Serum) – Mass Concentration
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
- 55883-3
- Short code
- Vit B12b Fld-mCnc
- Synonyms
- Vit B12b Fld-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 May Be Ordered
Your healthcare provider may recommend this test if you have symptoms like fatigue, weakness, numbness in hands/feet, balance problems, or unexplained anemia. It may also be checked during routine blood work or if you have conditions like pernicious anemia, celiac disease, or long-term vegan/vegetarian diet.
What to Expect Before the Test
No special preparation is needed. You may eat and drink normally before the test. A small needle will be used to draw blood from a vein in your arm. The process usually takes a few minutes.
What the Results Mean
Low levels may indicate vitamin B12 deficiency, which can cause anemia or nerve damage. High levels are less common but may be due to certain medications or genetic conditions. Your doctor will interpret results in relation to your symptoms and medical history.
Common Causes of Abnormal Results
Deficiency can result from poor diet, malabsorption issues (e.g., stomach/intestinal disorders), certain medications, or conditions like pernicious anemia. Overproduction is rare but may occur with some medications or genetic disorders.
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.
Clinical Significance
Short name
Vitamin B12 Serum
Frequently asked questions
What questions might I have about this test?
How often should I get this test?
What are the typical reference ranges for this test?
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