Quick Facts
- Sample: Blood
- Fasting: Fasting for at least 12 hours is required. Patient should stop biotin consumption at least 72 hours prior to the collection. Must be drawn before Schilling test, transfusions, or B12 therapy is started.
- Turnaround: 1-2 business days. May take longer based on weather, holiday, or lab delays.
What This Test Measures
This test measures the amount of vitamin B12 (also known as cobalamin) in your blood. Vitamin B12 is necessary for forming normal red blood cells, nerve function, and tissue and cellular repair. Your body does not produce it. Instead, it is absorbed after you eat foods such as red meat, poultry, fish, milk, eggs, and fortified products.
This is a single-marker test that reports one blood level of vitamin B12. It does not measure other vitamins or minerals, and it does not directly measure your dietary intake. It also does not provide a complete picture of your nutritional status. The result can help screen for a deficiency, but it cannot confirm one on its own.
Benefits
- Measures your vitamin B12 level in the blood with a single test
- Helps screen for a vitamin B12 deficiency
- Can support evaluation of symptoms such as fatigue, weakness, or dizziness
- Gives you results to review with your healthcare provider
Who Is This Test For?
- People with fatigue, weakness, dizziness, or a sore mouth or tongue
- People whose CBC with Differential detected large red blood cells
- People following a strict diet, such as one that excludes animal products
- People with conditions that may interfere with vitamin B12 absorption
- People with celiac disease, inflammatory bowel disease, or other conditions linked to low B12
How It Works
- Order Your Test Online
- Visit a Local Lab
- Get Results Online
FAQ
1. What is the purpose of this test?
This test measures your vitamin B12 level in the blood to help screen for a deficiency. Vitamin B12 supports normal red blood cell formation, nerve function, and tissue and cellular repair. A healthcare provider may use the result, along with your symptoms and other findings, to evaluate your vitamin B12 status. The test alone cannot diagnose a deficiency or any other condition.
2. Who should consider this test, and when?
You may consider this test if you have symptoms such as dizziness, weakness, fatigue, or a sore mouth or tongue. It may also be useful if a recent CBC with Differential detected large red blood cells, if you follow a strict diet that excludes animal products, or if you have a condition that can interfere with vitamin B12 absorption. Your healthcare provider can help decide whether it fits your situation. This test does not replace a medical or nutritional evaluation, and it does not provide a complete nutrition assessment.
3. How does this test differ from other nutritional tests?
Unlike a broader nutritional panel, this test reports only one marker — your vitamin B12 level — so it does not measure other vitamins, minerals, or nutrients, and it does not directly reflect how much vitamin B12 you eat. Because it is a blood measurement, results should not be compared directly with tests that use other specimen types or that measure other nutritional markers.
4. Do I need to fast before this test?
Yes. Fasting for at least 12 hours is required. Patient should stop biotin consumption at least 72 hours prior to the collection. This test must be drawn before a Schilling test, transfusions, or B12 therapy is started.
5. How quickly will I get results?
1-2 business days. May take longer based on weather, holiday, or lab delays.
6. How do I interpret the results?
The meaning of your vitamin B12 result depends on your symptoms, medical history, diet, supplements, medications, and other laboratory results. A single result does not always confirm or rule out a nutritional concern. Review your results with a qualified healthcare provider.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
7. What should I do if my results are abnormal?
Share your results with a qualified healthcare provider so they can review them alongside your symptoms, medical history, and other findings. Your provider will decide whether any additional evaluation is appropriate and can guide you on next steps. Do not make changes to supplements or medications without speaking with them first.
8. How often should I get tested?
How often you test depends on why you are being tested and your individual situation. This test is intended to help screen for a vitamin B12 deficiency, and more frequent testing is not always better. Your healthcare provider can advise whether you need repeat testing and when, so test as directed by your healthcare provider.
Pre-Test preparation
- Fasting for at least 12 hours is required.
- Patient should stop biotin consumption at least 72 hours prior to the collection.
- Must be drawn before Schilling test, transfusions, or B12 therapy is started.
