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Vitamin B12 Testing

You may be familiar with the vitamin known as B12. However, you may not be aware of the importance of this vitamin and how having a low level of Vitamin B12 can affect your health.

What is Vitamin B12?

Vitamin B12 is a vitamin that comes from animal food sources. These sources include dairy, eggs, and red meat. When you eat a food containing Vitamin B12, your body absorbs the vitamin in your intestines using a specific protein called intrinsic factor (IF) created by cells in your stomach.

According to the National Library of Medicine (NLM), Vitamin B12 is then used as an ingredient for many crucial chemical processes in the body, including making DNA and red blood cells and creating the specialized lining of your nerve cells known as the myelin sheath. This makes Vitamin B12 crucial for the proper functioning of your nervous system and the system involved in making new blood cells (hematologic system).

After a meal, any excess Vitamin B12 that you have absorbed gets stored in your liver. If you go without eating foods with Vitamin B12, your body can continue using Vitamin B12 by drawing on your liver stores.

Because Vitamin B12 is so vital for the basic function of your nervous and hematologic systems, when you don’t have a high enough level of Vitamin B12 in your blood, you can experience symptoms, notes the NLM.

These symptoms may include feeling very tired or weak, feeling numbness or tingling in your extremities, or feeling like you are off-balance.

Testing for Vitamin B12

Healthcare professionals can check for your level of Vitamin B12 and use the information to make decisions about how to improve your health. A follow-up Vitamin B12 lab test can help you see how lifestyle changes or medications (or both) are impacting your Vitamin B12 levels, which can help you make choices that can affect your future health outcomes.

Keeping your Vitamin B12 level within the advised range can help you avoid the consequences of low Vitamin B12 levels, such as problems with your nervous system or the way your body makes blood cells.

Who should get a Vitamin B12 test?

If you are interested in a health screening that checks your blood glucose level and cholesterol level, a Vitamin B12 test is another helpful tool to see how you are measuring up. If your Vitamin B12 test is slightly low, it can be helpful information that can help you make lifestyle changes, reports the NLM.

Beyond general screening, certain people should get a Vitamin B12 test. These groups are based on the three most common causes of a Vitamin B12 deficiency: a problem with absorbing B12 in the gut, not getting enough Vitamin B12 in the diet, and an autoimmune condition that attacks the intrinsic factor (IF) protein that is essential for helping your body break down and use Vitamin B12.

According to health experts at the Harvard University School of Public Health, up to 15 percent of people have a Vitamin B12 deficiency, and the following groups of people are at a higher risk of experiencing this condition:

  • People who avoid eating animal food sources: One of the most common causes of a Vitamin B12 deficiency is a vegan diet or any other eating pattern that directly avoids animal food sources such as eggs, red meat, or dairy.
  • People who have the autoimmune condition known as pernicious anemia: In this condition, the cells of the stomach that create intrinsic factors become damaged. This means that even if you are eating enough Vitamin B12, your body doesn’t have the tools it needs to absorb the vitamin and use it for its processes.
  • People who have acid reflux disease: People who struggle with gastroesophageal reflux disorder (GERD) may take medications to reduce their stomach acid. This can interfere with how Vitamin B12 gets released from food in the stomach.
  • The elderly: Elderly people have decreased stomach acid, which can interfere with how Vitamin B12 gets released from food in the stomach.
  • People who have had gastrointestinal surgeries: A stomach or intestinal surgery that removes a significant amount of tissue can remove the cells that help your body produce intrinsic factor (IF) or absorb Vitamin B12.
  • People who have specific gastrointestinal conditions: Illnesses like celiac disease or Crohn’s disease can decrease the absorption of Vitamin B12 in the gut.

People who abuse alcohol: Chronic alcoholism can reduce your body’s absorption of Vitamin B12, and people who drink heavily may be less likely to meet their dietary needs daily, as well.

How to get a Vitamin B12 test

There are two ways you can get a Vitamin B12 test: you can self-order either an in-person or at-home Vitamin B12 test through companies like Solv, Quest, LabCorp, etc, or you can visit with a healthcare provider and receiving a (referral/script) for one.

Depending on your specific medical situation, as well as any symptoms you may be having, your healthcare provider may recommend a Vitamin B12 test. This test may be particularly helpful if you have risk factors for a Vitamin B12 deficiency or if you are having unexplained symptoms of fatigue, weakness, numbness, or tingling.

When your healthcare provider orders a Vitamin B12 test, you may have the test performed at the clinic or an outside lab. You may also be able to order an at-home Vitamin B-12 test online without a healthcare provider’s order. However, this can make it difficult to interpret and act on results on your own, especially if your test results are abnormal.

What to expect during a Vitamin B12 test

Vitamin B12 is a simple blood test. Your healthcare provider may use a small needle to draw blood from a vein. The veins used are typically in your arm because these are usually the most easily accessed. The blood draw should cause minimal pain. Your Vitamin B12 test result may be available that same day, but the turn-around time depends on the laboratory. According to the NLM, you should fast (not eat or drink anything) for 6 to 8 hours before having a Vitamin B12 test. It’s important to tell your healthcare provider who orders the test about any medications that you take daily. This is because, according to the National Library of Medicine, certain medications can affect your test results, including medications for gout or seizure disorders.

Interpreting Vitamin B12 Test Results

After a Vitamin B12 test, you may be eager to know your results. Your result will appear as a single number within a specific range (the range varies depending on the kind of test used).

A healthcare provider can help you understand your Vitamin B12 level and how it fits into the context of your general health. You may be expecting a low number (for example, if you have a vegan diet), and you may be using the number as a starting point for beginning Vitamin B12 supplements. Or, you may be experiencing symptoms, which may be explained by a low Vitamin B12 result.

What to do if a Vitamin B12 test is low

If you have a Vitamin B12 result that is lower than the advised range, your healthcare provider can help you determine your next steps. This may include lifestyle changes (such as deliberately trying to include more animal food sources in your diet) or starting on a Vitamin B12 supplement. If your level is extremely low and you are having severe symptoms, further testing may be needed.

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