Vitamin B12 (Cobalamin) Most Popular

The Vitamin B12 (Cobalamin) test contains 1 test with 1 biomarker.

Brief Description: The Vitamin B12 test measures the levels of vitamin B12 in the blood, which is an essential nutrient for various bodily functions. It assesses the concentration of vitamin B12 to evaluate its availability for proper red blood cell production, nervous system function, and DNA synthesis. The test helps diagnose vitamin B12 deficiency or monitor the effectiveness of vitamin B12 supplementation.

Also Known As:  B12 Test, Cobalamin Test, Vitamin B12 test, Serum B12 Test 

Collection Method: Blood Draw 

Specimen Type: Serum 

Test Preparation: No preparation required. 

When is a Vitamin B12 test ordered?  

A Vitamin B12 test may be ordered in several situations to assess a patient's vitamin B12 levels:

1. Evaluation of Anemia: When a patient presents with symptoms of anemia such as fatigue, weakness, or shortness of breath, a Vitamin B12 test is ordered to determine if the anemia is due to a deficiency in vitamin B12.

2. Evaluation of Neuropsychiatric Symptoms: Symptoms such as numbness or tingling in the extremities, memory problems, depression, or confusion may indicate a vitamin B12 deficiency. The test helps assess vitamin B12 levels as a potential cause for these symptoms.

3. Evaluation of Malabsorption Conditions: Patients with certain gastrointestinal disorders or conditions affecting the absorption of nutrients, such as pernicious anemia or celiac disease, may require a Vitamin B12 test to assess their vitamin B12 levels.

4. Monitoring Vitamin B12 Supplementation: For individuals receiving vitamin B12 supplementation, the test is ordered to monitor the effectiveness of the supplementation and ensure that the desired vitamin B12 levels are being achieved.

What does a Vitamin B12 blood test check for? 

Vitamin B12 is a member of the vitamin B complex. It is required for the creation of normal red blood cells, tissue and cell healing, and the synthesis of DNA, the genetic material in cells. Vitamin B12 is a nutrient that the body cannot make and must be obtained through the diet. 

Vitamin B12 deficiency is detected by measuring vitamin B12 in the liquid portion of the blood. 

A B12 deficiency can cause macrocytic anemia, which is characterized by red blood cells that are bigger than normal. Megaloblastic anemia is a kind of macrocytic anemia marked by the generation of fewer but larger RBCs known as macrocytes, as well as cellular abnormalities in the bone marrow. Reduced white blood cell and platelet count are two other test results linked to megaloblastic anemia. 

B12 is also necessary for nerve function, and a lack of it can induce neuropathy, which causes tingling and numbness in the hands and feet of those who are affected. 

B12 deficiency is most commonly caused by a lack of vitamin B12 in the diet or supplements, insufficient absorption, or an increased requirement, such as during pregnancy. 

Lab tests often ordered with a Vitamin B12 test: 

When a Vitamin B12 test is ordered, it is often part of an investigation into symptoms such as anemia, neuropathy, or cognitive disturbances that could be related to B12 deficiency. Additional tests may be ordered to confirm the diagnosis, determine the cause of the deficiency, and to assess the overall health of the patient. Here are some tests that are commonly ordered alongside a Vitamin B12 test:

1. Complete Blood Count (CBC):

   • Purpose: To evaluate overall blood health and to detect anemia and macrocytosis (enlarged red blood cells), which can be a sign of B12 deficiency.
   • Why Is It Ordered: B12 deficiency often leads to a decrease in red blood cell production and can cause a type of anemia called megaloblastic anemia.

2. Folate (Folic Acid):

   • Purpose: Like Vitamin B12, folate is necessary for the production of DNA and red blood cells.
   • Why Is It Ordered: To differentiate between B12 and folate deficiencies, as they can present with similar clinical pictures and have a closely related role in cellular metabolism.

3. Methylmalonic Acid (MMA):

   • Purpose: Elevated levels of MMA can indicate a B12 deficiency, even when B12 levels are borderline normal.
   • Why Is It Ordered: To provide more specific information about B12 activity at the cellular level, as MMA levels increase when B12 is deficient.

4. Homocysteine:

   • Purpose: Homocysteine levels can be elevated in B12 deficiency as well as in folate deficiency.
   • Why Is It Ordered: Elevated homocysteine can be harmful to cardiovascular health and can help confirm a deficiency even when B12 levels are normal.

5. Intrinsic Factor Antibody:

   • Purpose: To determine if pernicious anemia, which is an autoimmune condition that affects absorption of B12, is the cause of the deficiency.
   • Why Is It Ordered: Positive intrinsic factor antibodies suggest that the immune system is attacking the cells in the stomach that allow B12 to be absorbed.

6. Gastrin:

   • Purpose: Gastrin levels can be elevated in individuals with pernicious anemia.
   • Why Is It Ordered: To help diagnose pernicious anemia, especially when the intrinsic factor antibody test is inconclusive.

7. Reticulocyte Count:

   • Purpose: To measure how fast new red blood cells are being made by your bone marrow and released into the blood.
   • Why Is It Ordered: To assess bone marrow function, particularly after B12 supplementation has begun, to determine if the treatment is effective.

8. Liver Function Tests:

   • Purpose: To evaluate the health of the liver, which can also store Vitamin B12.
   • Why Is It Ordered: To rule out liver disease as a cause of abnormal B12 levels and because liver disease can affect the metabolism of B12.

9. Serum Iron and Iron Binding Capacity:

   • Purpose: These tests measure the amount of iron in your blood and your body's capacity to transport iron.
   • Why Is It Ordered: To assess for iron deficiency, which can coexist with B12 deficiency and also cause anemia.

10. Lactate Dehydrogenase (LDH):

    • Purpose: An enzyme that might be elevated in cases of tissue damage or cellular turnover.
    • Why Is It Ordered: It can be used to evaluate the extent of hemolysis or cellular damage associated with severe anemia.

Each of these tests adds information that can help determine the cause of the symptoms, monitor the effectiveness of treatment, and manage overall health. The specific tests ordered will depend on the individual's clinical picture, the doctor's suspicion of possible related conditions, and the initial test results.

Conditions where a Vitamin B12 test is recommended:

A Vitamin B12 test is commonly ordered for:

1. Vitamin B12 Deficiency: The test helps diagnose and monitor vitamin B12 deficiency, which can lead to conditions such as megaloblastic anemia, neurological abnormalities, or pernicious anemia.

2. Pernicious Anemia: Pernicious anemia is an autoimmune condition where the body is unable to absorb vitamin B12 properly. The Vitamin B12 test is used to diagnose and monitor this condition.

3. Gastrointestinal Disorders: Conditions that affect the absorption of nutrients, such as Crohn's disease, celiac disease, or gastric bypass surgery, may require a Vitamin B12 test to assess vitamin B12 levels.

How does my healthcare provider use a Vitamin B12 test? 

Health care providers use the results of a Vitamin B12 test to:

1. Diagnose Vitamin B12 Deficiency: Abnormal test results indicating low vitamin B12 levels help healthcare providers diagnose and evaluate the severity of vitamin B12 deficiency.

2. Guide Treatment and Supplementation: Based on the test results, healthcare providers can recommend appropriate vitamin B12 supplementation, dosage, or dietary changes to address deficiencies and improve vitamin B12 levels.

3. Monitor Treatment Response: Regular testing allows healthcare providers to monitor the effectiveness of vitamin B12 supplementation or treatment interventions and make adjustments as needed.

By effectively utilizing the results of a Vitamin B12 test, healthcare providers can assess vitamin B12 status, diagnose deficiencies, and implement interventions to improve overall health and mitigate associated symptoms and risks.

What do my Vitamin B12 test results mean? 

Normal B12 and folate levels may indicate that a person does not suffer from a deficiency and that the signs and symptoms they are experiencing?are caused by something else. Normal levels, on the other hand, may indicate that a person's stored B12 and/or folate has not yet been depleted. 

A health practitioner may order a methylmalonic acid test as an early sign of B12 deficiency if a B12 level is normal but a deficiency is still suspected. 

A low B12 and/or folate level in a person with signs and symptoms implies a deficiency, although it does not always indicate the severity of the anemia or related neuropathy. Additional tests are frequently performed to determine the source of the deficit. Low B12 or folate levels can be caused by a variety of factors. 

Dietary folate or B12 deficiency, which?is uncommon in the United States. It can be evident in people who are malnourished in general and vegans who do not eat any animal products. Folate deficiency has become extremely rare since the development of fortified cereals, breads, and other grain products. 

Both B12 and folate deficits can be caused by diseases that prevent them from being absorbed in the small intestine. These may include the following: 

• Pernicious anemia 
• Celiac disease 
• Crohn's disease and ulcerative colitis are examples of inflammatory bowel disease. 
• Bacterial overgrowth or the presence of parasites in the intestines, such as tapeworms 
• Long-term usage of antacids or H2 proton pump inhibitors reduces stomach acid production. 
• Absorption can be considerably reduced by surgery that removes part of the stomach or the intestines, such as gastric bypass. 
• Insufficiency of the pancreas 
• Chronic alcoholism or heavy drinking 
• Some treatments, such as metformin, omeprazole, methotrexate, or anti-seizure medications like phenytoin, are used. 
• Increased requirements for healthy fetal development, all pregnant women require an increased amount of folate and are advised to consume 400 micrograms of folic acid every day. The need for folate is higher in those who have cancer that has spread or who have chronic hemolytic anemia. 
• Smoking 

If a person is being treated for a B12 or folate deficit with supplements, normal or higher findings suggest that the treatment is working. 

High amounts of B12 are uncommon, and they aren't routinely evaluated clinically. If a person has a condition such chronic myeloproliferative neoplasm, diabetes, heart failure, obesity, AIDS, or severe liver disease, their vitamin B12 level may be elevated. High B12 levels can also be caused by using estrogens, vitamin C, or vitamin A. 

Most Common Questions About the Vitamin B12 test:

What is a Vitamin B12 test?

A Vitamin B12 test is a blood test that measures the amount of vitamin B12 in your blood. Vitamin B12 is vital for the production of healthy red blood cells and nerve cells, and it aids in the creation of DNA.

Basics of the Vitamin B12 Test

Why might my healthcare provider order a Vitamin B12 test?

Your healthcare provider might order a Vitamin B12 test if you have symptoms of a B12 deficiency, such as weakness, fatigue, loss of appetite, weight loss, and anemia. Other symptoms could include balance problems, depression, confusion, dementia, poor memory, and soreness of the mouth or tongue.

What can cause a Vitamin B12 deficiency?

Vitamin B12 deficiency can occur due to a diet lacking in vitamin B12, typically seen in vegetarians and vegans, as B12 is primarily found in animal products. Certain conditions can also cause B12 deficiency, like pernicious anemia, celiac disease, Crohn's disease, and certain medications, like antacids and some type 2 diabetes drugs.

Understanding the Results

What is the normal range for a Vitamin B12 test?

The normal range for a Vitamin B12 test is typically defined as between 200 and 1100 picograms per milliliter (pg/mL), but this can vary slightly depending on the patient's age.

What do low levels in a Vitamin B12 test mean?

Low levels of Vitamin B12 in the blood can suggest a deficiency, which can lead to anemia and neurological problems. This could be due to insufficient intake from the diet, malabsorption issues, or certain disorders like pernicious anemia.

What do high levels in a Vitamin B12 test mean?

High levels of Vitamin B12 can be associated with diseases such as liver disease, certain types of leukemia, or can occur in response to high-dose vitamin B12 supplementation.

Vitamin B12 Test and Related Conditions

Can a Vitamin B12 test diagnose pernicious anemia?

Yes, a Vitamin B12 test is a key component in diagnosing pernicious anemia, a condition where the body can't absorb enough B12 due to lack of intrinsic factor, a protein made in the stomach that is necessary for B12 absorption.

How can a Vitamin B12 test help in the diagnosis of dementia or mental decline?

While the Vitamin B12 test alone can't diagnose dementia, a deficiency in Vitamin B12 can cause symptoms of mental decline. If a person has dementia-like symptoms, a healthcare provider may order a Vitamin B12 test to see if a deficiency is contributing to the symptoms.

Can a Vitamin B12 test be used to monitor the effectiveness of treatment in patients with Vitamin B12 deficiency?

Yes, if you are being treated for B12 deficiency, your healthcare provider may order a Vitamin B12 test to monitor the effectiveness of the treatment and adjust the dosage or frequency of supplementation as necessary.

Vitamin B12 Test and Lifestyle

Can I improve my Vitamin B12 levels with dietary changes?

Yes, consuming a diet high in animal products like fish, meat, poultry, eggs, milk, and other dairy products can improve your B12 levels. For vegetarians or vegans, there are B12 fortified foods like cereals, non-dairy milks, and nutritional yeast.

Can the Vitamin B12 test help identify the cause of my fatigue?

If your fatigue is due to Vitamin B12 deficiency, the Vitamin B12 test can help identify this cause. However, fatigue can be due to numerous reasons and is often a nonspecific symptom, so other tests may be needed to determine the exact cause.

Can an excessive consumption of alcohol affect the Vitamin B12 test results?

Yes, excessive consumption of alcohol can lead to malabsorption issues, which can lower the levels of Vitamin B12 in your blood and affect the test results.

How does vegetarianism or veganism affect Vitamin B12 levels?

Vegetarian and especially vegan diets can lead to B12 deficiency as the vitamin is naturally found in animal products. Therefore, those following such diets might need to rely on fortified foods or supplements to get enough B12.

Can I take over-the-counter vitamin B12 supplements without a doctor's prescription?

While you can take over-the-counter vitamin B12 supplements without a prescription, it's best to talk to your healthcare provider first, especially if you're planning to take a high dose. Too much vitamin B12 can cause side effects and interact with certain medications.

Can diseases other than pernicious anemia also cause vitamin B12 deficiency?

Yes, other than pernicious anemia, diseases like celiac disease, Crohn's disease, and certain stomach surgeries can affect the body's ability to absorb vitamin B12, leading to a deficiency.

Can a Vitamin B12 test be used in diagnosing mental health conditions?

While the Vitamin B12 test itself cannot diagnose mental health conditions, research has shown a correlation between low levels of vitamin B12 and mood disorders such as depression. More research is needed, however, to fully understand this relationship. It's important to have a holistic approach when diagnosing and treating mental health conditions, and a healthcare provider may consider a Vitamin B12 test as part of a broader diagnostic process.

Is a Vitamin B12 test necessary for people with no symptoms?

Routine Vitamin B12 testing isn't necessary for everyone. However, certain groups of people are at higher risk for B12 deficiency and might benefit from periodic testing. This includes older adults, people with vegetarian or vegan diets, and people with certain health conditions or who take certain medications.

Can medications interfere with Vitamin B12 absorption?

Yes, some medications, such as proton pump inhibitors and metformin, a common medication for type 2 diabetes, can interfere with B12 absorption in the body, potentially leading to a deficiency over time.

Can I maintain optimal Vitamin B12 levels through diet alone?

Many people can maintain adequate Vitamin B12 levels through diet alone, particularly by consuming B12-rich foods like meat, fish, eggs, dairy, and fortified plant-based foods. However, certain groups of people, such as older adults and those with certain health conditions, might need supplements to maintain optimal levels.

How does smoking affect Vitamin B12 levels?

Smoking can lower the body's ability to absorb vitamin B12, possibly leading to a deficiency. If you smoke, this might be another reason to get your vitamin B12 levels checked.

What are the risks associated with Vitamin B12 deficiency?

Long-term vitamin B12 deficiency can lead to irreversible nerve damage. It can also cause symptoms of anemia, including fatigue, weakness, and shortness of breath, and can increase levels of homocysteine, a type of amino acid, which has been linked to an increased risk of heart disease.

Are there any symptoms of too much Vitamin B12?

Excess vitamin B12 does not typically cause symptoms because it is a water-soluble vitamin, and the body can eliminate excess amounts through the urine. However, taking extremely high dosesof B12 supplements can lead to side effects like dizziness, headache, anxiety, nausea, and vomiting. It's always best to consult with a healthcare provider before starting any new supplement regimen.

How does pregnancy affect Vitamin B12 levels?

Pregnancy increases the body's demand for B12 for fetal development. Therefore, pregnant women have a higher risk of B12 deficiency, especially if they do not consume enough through their diet. Healthcare providers often monitor B12 levels during pregnancy to ensure the health of both mother and baby.

Does age affect Vitamin B12 levels?

Yes, as people age, their body's ability to absorb Vitamin B12 can decrease due to changes in stomach acidity. This can lead to a higher risk of deficiency in older adults.

Are there any other tests that might be ordered along with a Vitamin B12 test?

A healthcare provider might also order a folate, homocysteine, or methylmalonic acid (MMA) test, as these levels can also be affected by B12 levels. An intrinsic factor antibody test may also be ordered if pernicious anemia is suspected.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.