Vitamin B12 (Serum or Plasma Concentration)
This test measures the amount of vitamin B12 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 or nerve damage."]
Key facts at a glance
- LOINC
- 109690-8
- Short code
- FLUBV Ag Msmt Nph
- Synonyms
- FLUBV Ag Msmt Nph
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 7.35
- Ref high
- 7.45
- Critical range
- 7.2 N/A – 7.6 N/A
- 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 Is This Test Done?
Your healthcare provider may order this test if you have symptoms like fatigue, weakness, numbness, or tingling in your hands and feet. It may also be done to check for vitamin deficiencies, especially in people who follow strict vegetarian or vegan diets, have certain gastrointestinal conditions, or take medications that interfere with vitamin absorption.
What to Expect Before the Test
No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw blood. If you’re on blood thinners, let your provider know before the test.
What Happens During the Test?
A healthcare professional will collect a blood sample from a vein in your arm. The sample is then sent to a lab for analysis. Results are typically available within a few days.
What the Results Mean
Low levels of vitamin B12 can indicate deficiencies, which may require dietary changes, supplements, or medical treatment. High levels may be due to certain medical conditions or medications.
Reference range
NCBI: pH 7.35-7.45N/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 health problems, including pernicious anemia, nerve damage, or cognitive issues. Regular monitoring is important for those at higher risk.
Short name
Vitamin B12 Level
Frequently asked questions
What causes low vitamin B12 levels?
How long does it take to get results?
Can I eat or drink anything before the 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