Vitamin B12 (Serum) – Mass Concentration
This test measures the amount of vitamin B12 (also called cobalamin) in your blood serum. Vitamin B12 is essential for nerve function, red blood cell production, and DNA synthesis.
["Vitamin B12 helps prevent serious health issues like anemia or nerve damage."]
Key facts at a glance
- LOINC
- 35201-3
- Short code
- Vit B12 Ser-msCnc
- Synonyms
- Vit B12 Ser-msCnc
- 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, weakness, numbness in hands/feet, or trouble with balance. It’s also used to screen for pernicious anemia, vitamin B12 deficiency, or conditions like celiac disease, gastric surgery, or certain medications that may interfere with absorption.
What to Expect Before the Test
No special preparation is needed, but you may be asked to fast for 8–12 hours before the draw if your lab uses a different method. Wear a loose shirt for easy access to your arm.
What Happens During the Test
A healthcare provider will insert a small needle into your vein (usually in your arm) to draw blood. The process takes about 5 minutes. You may feel a brief pinch, but it’s usually over quickly.
What the Results Mean
Results are compared to a general reference range for healthy adults. Low levels may indicate deficiency, while high levels could signal conditions like kidney disease or certain cancers. Your doctor will interpret results in the context of your symptoms and medical history.
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.
Vitamin B12 deficiency can lead to serious complications, including megaloblastic anemia (large, immature red blood cells), neurological issues (e.g., memory problems, vision changes), or even long-term nerve damage. Early detection and treatment (e.g., supplements or injections) can prevent these problems. High levels may require further investigation to rule out underlying conditions like chronic kidney disease or certain cancers.
Short name
Vitamin B12 Level
Frequently asked questions
How long does it take to get my results?
Can I take supplements before the test?
What if my results are outside the normal range?
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