Vitamin B12 (Cobalamin) with Serum or Plasma
This test measures the amount of vitamin B12, an essential nutrient important for nerve function and red blood cell production, in your blood.
["Vitamin B12 helps prevent anemia and supports brain health."]
Key facts at a glance
- LOINC
- 41487-0
- Short code
- C parvum Ag Stl Ql IA
- Synonyms
- C parvum Ag Stl Ql IA
- Category
- coagulation
- Sample
- stool
- Container
- Clean container
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ia
- Specimen volume
- 5 g
- Stability
- Refrigerated: 24h, Frozen: 7d
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Your doctor may order a vitamin B12 test if you have symptoms like fatigue, weakness, numbness, or balance issues. It may also be checked during routine blood work, pregnancy, or if you have conditions like pernicious anemia, celiac disease, or other nutrient deficiencies.
What to Expect Before the Test
No special preparation is needed. You may eat and drink normally before the test. If you’re on certain medications (like certain antacids or proton pump inhibitors), let your doctor know, as they might affect results.
During the Test
A healthcare provider will draw blood from a vein in your arm. You may feel a slight pinch, but it usually takes only a few minutes. You can resume normal activities afterward.
Possible Results and Next Steps
Results may be low, normal, or high. Low levels could indicate vitamin B12 deficiency, which may require supplements or medical treatment. High levels are less common but may need further investigation.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low vitamin B12 levels can lead to anemia, nerve damage, or cognitive issues. Early detection helps prevent long-term complications. Your doctor will discuss results and recommend follow-up if needed.
Short name
Vitamin B12 Level
Frequently asked questions
What causes vitamin B12 deficiency?
How long does it take to get results?
Can I take vitamin B12 supplements before testing?
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