Vitamin B12 (Cobalamin)

Description: A Vitamin B12 test is a blood test that measures the level of Vitamin B12 in the blood’s serum and is used to detect Vitamin B12 deficiency.

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?  

When a complete blood count and/or blood smear, performed as part of a health checkup or anemia evaluation, reveal a low red blood cell count with the presence of big RBCs, vitamin B12 levels may be ordered. A high mean corpuscular volume implies that the RBCs have grown in size. 

When a person exhibits the following signs and symptoms of a deficit, testing for B12 levels may be necessary: 

• Diarrhea 

• Dizziness 

• Muscle weakness, fatigue 

• Appetite loss. 

• Skin that is pale 

• Irregular heartbeats, rapid heart rate 

• Breathing problems 

• Tongue and mouth ache 

• In the feet, hands, arms, and legs, there is tingling, numbness, and/or burning 

• Confusion or obliviousness 

• Paranoia 

When a person is at risk of deficiency, such as those with a history of malnutrition or a condition associated to malabsorption, B12 tests may be required. 

Individuals being treated for malnutrition or a B12 or folate deficit may have these tests done on a frequent basis to see how effective their treatments are. This could be part of a long-term therapy plan for people who have a disease that causes chronic deficiency.  

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: 

• Folate 

• Methylmalonic Acid (MMA) 

• Homocysteine 

• Vitamin B1 

• Vitamin B2 

• Vitamin B3 

• Vitamin B5 

• Vitamin B6 

• Vitamin B7 

• Rheumatoid factor 

Conditions where a Vitamin B12 test is recommended:

• Vitamin B12 Deficiency 

• Pernicious Anemia 

• Nerve Damage 

• Malabsorption 

• Malnutrition 

How does my health care provider use a Vitamin B12 test? 

Vitamin B12 and folate are frequently used in conjunction to detect deficiencies and to aid in the diagnosis of anemias such as pernicious anemia, an inflammatory condition that inhibits B12 absorption. 

B12 and folate are two vitamins that the body cannot generate and must be obtained from the diet. They are essential for the creation of normal red blood cells, tissue and cell repair, and the synthesis of DNA, the genetic material in cells. B12 is required for normal nerve function. 

B12 and folate tests can also be used to assess someone who is experiencing mental or behavioral changes, especially in the elderly. A B12 test can be ordered with or without folate, as well as with other screening laboratory tests like a complete blood count, comprehensive metabolic panel, antinuclear antibody, C-reactive protein, and rheumatoid factor to help determine why a person is exhibiting signs and symptoms of a nerve condition. 

B12 and folate tests can also be performed in conjunction with a variety of other tests to assess a person's overall health and nutritional status if they have signs and symptoms of substantial malnutrition or dietary malabsorption. People with alcoholism, liver disease, stomach cancer, or malabsorption diseases including celiac disease, inflammatory bowel disease, or cystic fibrosis may fall into this category. 

Testing may be performed to assess the success of treatment in patients with known B12 and folate deficits. This is especially true for people who cannot absorb B12 and/or folate effectively and must be treated for the rest of their lives. 

Folate levels in the blood's serum might fluctuate depending on a person's recent diet. Because red blood cells contain 95 percent of circulating folate, a test to evaluate folate levels inside RBCs could be employed instead of or in addition to the serum test. Some doctors believe that the RBC folate test is a better predictor of long-term folate status and is more clinically useful than serum folate, however there is no consensus on this. 

Homocysteine and methylmalonic acid are two more laboratory tests that can be used to detect B12 and folate deficits. In B12 deficiency, both homocysteine and MMA are high, whereas in folate deficit, only homocysteine, not MMA, is elevated. This distinction is critical because treating anemia with folate treats the anemia but not the brain damage, which may be irreparable. 

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. 

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