Vitamin B12 Deficiency and Upper Endoscopy Testing- What to Expect

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Vitamin B12 deficiency is diagnosed with a simple blood test.  Determining the cause of B12 deficiency is another matter.  One test used to find out why your vitamin B12 levels are low is an upper endoscopy, or esophagogastroduodenoscopy (EGD). Here’s what you should expect when visiting your gastroenterologist for this simple procedure.

Vitamin B12 Deficiency and Upper Endoscopy Testing- What to Expect

What’s causing vitamin B12 deficiency?

Some of the causes of vitamin B12 deficiency are easy enough to figure out without undergoing invasive testing.  If you follow a strict vegan diet, have had a gastric bypass, or take medications like metformin or PPI’s, then you are at risk for developing vitamin B12 deficiency.

But what if you don’t fall into any of those categories? If you’ve been taking your vitamin B12 supplements and still experience symptoms of fatigue, loss of appetite, or acid reflux, then your physician may suggest an endoscopy to determine if there has been any damage to your esophagus, stomach, or duodenum.

What is an endoscopy?

An endoscopy is a procedure that involves inserting a long flexible tube in your mouth that extends through your throat, past your esophagus and stomach, and all the way to the uppermost part of your small intestines, the duodenum.  At the end of the tube is a small camera that enables your doctor to view your stomach and esophageal linings.

Although the entire procedure takes minutes, it requires light sedation, so plan to have somebody else drive you home afterwards.


  • Prior to your visit, you will be instructed to fast for eight hours.  That means no eating or drinking, so that your doctor will get a clear view of your stomach.
  • You will be given a mild sedative and painkillers.
  • Next, your doctor will spray a local anesthetic in your throat in order to suppress gagging or coughing.
  • You will be asked to bite down on a mouth guard, in order to protect your teeth during the procedure.

During the endoscopy

  • Once you are sufficiently sedated, the gastroenterologist will begin the test.
  • You will be asked to swallow a few times while the tube is gently inserted into your throat.
  • You should be able to breathe comfortably throughout the procedure.
  • During the endoscopy, your doctor will need to blow air into the probing unit, in order to see the inside of your stomach and detect any abnormalities.  You may experience a feeling of bloating or fullness.
  • Sometimes, a biopsy is taken, but you will experience no pain.


  • After the test is completed, you will not be allowed to leave until you are sufficiently awake.
  • Your throat may feel sore for a day or two following the testing.
  • Follow your doctor’s advice regarding eating after the endoscopy.
  • Any unusual symptoms like severe stomach cramps or bleeding should be reported immediately.


If your doctor finds any abnormalities while reviewing your endoscopy, it could signify one of several conditions, including:

  • Celiac disease, which correlates with vitamin B12 deficiency
  • Gastritis, which also causes vitamin B12 deficiency
  • GERD, another illness that occurs with vitamin B12 deficiency
  • Ulcer

Please tell us…

Do you suffer from vitamin B12 deficiency? If so, do you know what is causing your low vitamin B12 levels?
Do you have any questions or suggestions?  Please leave your comments below.

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EGD – esophagogastroduodenoscopy