Serum or Plasma Substance Concentration for Vitamin B12 (Qualitative or Quantitative)
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
- 23689-3
- Short code
- CDV AB
- Synonyms
- CDV Ab Ser Ql IF
- Category
- chemistry
- Sample
- serum
- Container
- Red-top serum separator tube (SST) or plain red-top tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Immunofluorescence (IFA)
- Specimen volume
- 1-2 mL of serum
- Stability
- Stable for 7 days at 2-8°C; for longer storage, freeze at -20°C or below
- Hemolysis max
- 2
- Lipemia max
- 3
- Icterus max
- 2
- TAT
- 24–72 hours
- Order
- routine
Why Is This Test Done?
Your doctor may order a vitamin B12 test to check for deficiencies, which can cause fatigue, weakness, numbness, or balance problems. It may also be done if you have symptoms like unexplained anemia, digestive issues, or neurological symptoms. Sometimes, it’s part of a routine checkup or screening for conditions like pernicious anemia or other vitamin deficiencies.
What to Expect Before the Test
No special preparation is usually needed. You may be asked to fast for a few hours before the blood draw, but this depends on your doctor’s instructions. Bring any medications you’re taking, as some can affect results.
How the Test Is Done
A healthcare provider will take a blood sample from a vein in your arm using a small needle. You may feel a brief pinch, but it usually doesn’t cause much discomfort. The blood is then sent to a lab for testing.
What the Results Mean
Results can be either qualitative (yes/no presence) or quantitative (exact amount). Low levels may indicate a deficiency, while high levels might suggest conditions like certain cancers or liver disease. Your doctor will interpret the results in the context of your health history and symptoms.
Reference range
Negative: No antibodies detected; Positive: Antibodies detected (titer reported as endpoint dilution)N/A
No special patient preparation required. Sample should be collected prior to administration of blood products or vaccines when possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Vitamin B12 deficiency can lead to serious health problems if left untreated, including anemia (reduced red blood cells), nerve damage, and cognitive issues. Early detection helps prevent complications and allows for treatment with supplements or dietary changes. High levels may require further investigation to rule out underlying conditions.
Short name
Vitamin B12 Level
Frequently asked questions
How long does it take to get my results?
Can I eat or drink anything before the test?
What if my results are abnormal?
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 15, 2026. · Read our editorial policy