Vitamin B12 Test

Vitamin B₁₂ is absorbed in the small intestines and then makes its way to the blood and cells. The body also stores vitamin B₁₂ in the liver for future use. Vitamin B₁₂ is essential in supporting the nervous system, making red blood cells, and creating DNA (the genetic material present in our cells). Vitamin B₁₂ must be supplied by the diet or supplementation because the body is not able to produce it independently. It is naturally found in animal proteins, such as red meat, fish, poultry, eggs, and dairy. Plant foods are not a reliable source of vitamin B12 unless they are fortified. Low levels of vitamin B₁₂ may occur if you do not consume enough vitamin B₁₂ or the body does not store or absorb enough of the vitamin. People who are deficient in vitamin B₁₂ may or may not have any symptoms of anemia (a condition in which your body does not have enough healthy red cells to carry oxygen to your body’s tissues) or nerve damage. Early detection is important to prevent irreversible damage over time, especially to the nervous system.

People with low levels of vitamin B₁₂ may not have any symptoms or may have symptoms of anemia or nerve damage. General symptoms related to anemia and nerve damage include fatigue, weakness, difficulty concentrating, depression, numbness or tingling in the hands and feet, headaches, moodiness, and gastrointestinal symptoms.

Symptoms:

• Red or painful tongue
• Fatigue
• Pale or yellow skin color
• Pounding sound in ears (tinnitus)
• Bruising
• Impaired ability to do activities requiring physical exertion (exercise intolerance)
• Frequent infections
• Headaches
• Muscle weakness
• Constipation
• Unintentional weight loss
• Dizziness or lightheadedness
• Abnormally rapid heartbeat
• Foggy thinking, poor memory
• Shortness of breath
• Difficulty walking
• Problems with balance
• Numbness or tingling in hands and feet
• An intense craving to chew and eat ice, eat nonfood items, or both (pica)
• Changes to mood or sleep (depression, irritability, panic attacks, insomnia)

If you are experiencing severe symptoms, such as abnormal heartbeat, heart flutters, fainting, shortness of breath, extreme fatigue, unsteady gait, or severe bruising, speak with your healthcare provider before purchasing this test.

You must be 18 years of age or older to purchase a test on questhealth.com. This test requires specimen collection at a Quest Diagnostics location or through Quest Mobile™, a convenient option for in-home sample collection*. Collection not available in AK, AZ, or HI. 

*Check your zip code here for service availability, not available in all locations.