Vitamin B12 Test

Vitamin b12

Last Updated December 20th, 2021

What is vitamin b12?

Vitamin b12 is an essential nutrient vital to your nervous system and the level of red blood cells. It is also involved in the synthesis of DNA. Since it is required for the development of genetic material and tissues, this vitamin is of extreme importance in pregnant women and the developing fetus.

Why should you get tested for vitamin b12?

Though this essential vitamin is found abundantly in food, it is estimated that 15% of the American population might be deficient in vitamin b12. If someone shows symptoms of anemia such as fatigue, confusion, and irregular heartbeat, the doctor may prescribe this test. Additionally, if one shows classic symptoms of pernicious anemia such as pale skin and unexplained weight loss, he/she should ideally undergo this blood test.

Also, if you have high serum folate levels (vitamin b9) then your doctor might ask you to undergo this test. This is because high folate levels can mask the symptoms of vitamin b12 deficiency causing it to become more serious and dangerous in the longer run.

What are the symptoms of vitamin b12 deficiency?

As mentioned above, the symptoms of vitamin b12 deficiency are seen as – fatigue, pallor, weakness, confusion, depressive tendencies, sudden weight loss, tingling/numbness in limbs, balance issues, oral sores, and loss of appetite.

What can cause vitamin b12 deficiency?

The most important factor in the absorption of vitamin b12 is the presence of healthy levels of stomach acid. If a person has insufficient or excessive levels of these digestive acids, there will be poor absorption of vitamin b12 in the body. Thus, having chronic digestive disorders such as celiac disease, Crohn’s disease, etc can lead to vitamin b12 deficiency. Similarly, if you have undergone a gastric bypass surgery there is a high risk of this deficiency. Several medications such as PPIs can also affect vitamin b12 absorption.

Children and older adults also tend to absorb vitamin b12 poorly. It has been noted that vegans and vegetarians also show a high tendency of this nutrient deficiency. This is because meat and poultry products are the main sources of vitamin b12 in our diet.

How is the vitamin b12 test done?

Vitamin b12 test can be done as a blood test. In most cases, it is not required to fast before this test. However, in case the blood sample would be tested for other blood components such as CBC, then your doctor may ask you to refrain from consuming anything 6-8 hours before the test (except for water).
During the test, a blood sample is collected from the arm or the elbow. This area is cleaned with an antiseptic and in some cases, a tight band might be tied across the arm to increase the blood flow. A needle is inserted in the vein and a small sample of blood is drawn.  The site of injection is covered with a small bandage.

How should one prepare for this test?

This is a very simple and routine test and requires no special preparation. If you are undergoing the blood test just for vitamin b12, you needn’t fast before the test. In case, this test has been coupled with few other tests, then depending on those fasting may or may not be required.

Is fasting required before undergoing vitamin b12 test?

No, there is no need to fast before a vitamin b12 blood test.

What is the cost of vitamin b12 test in India?

The general cost of vitamin b12 test in India lies between Rs. 800-1000.

What are the normal ranges of vitamin b12 in the body?

Vitamin b12 level is expressed in terms of pictograms/milliliter (pg/mL).

Vitamin B12 level Range
< 150 pg/mLLow
200-800 pg/mlNormal
>800 pg/mLHigh
A reading that lies within the 200-600 pg/mL is considered to be normal. Below 150 pg/mL is counted as low and above 800 pg/mL is counted as high vitamin b12. 

How soon can I get the results?

It usually takes 24-36 hours for the test results to come. This means you get your test results 1-2 days after the test is conducted.

What do the results mean?

It is important to note that several drugs tend to affect the vitamin b12 level in your body.  Always inform your doctor about the medications you are on before going for the blood test.

What should I do if I have abnormal levels of vitamin b12?

If you have low vitamin b12 (< 200 pg/mL), it would mean that you have – vitamin b12 deficiency, pernicious anemia, or an overactive thyroid. A low level indicates high chances of neurological disorder.

A high vitamin b12 level (>800 pg/mL) often indicates an issue pertaining to the liver or the kidneys. It could also indicate diabetes or be a precursor to leukemia.

Is high vitamin b12 level in blood dangerous?

Both, abnormally low and abnormally high levels of vitamin b12 in the body are indicators of serious health issues. Both may cause life-threatening complications too. If you have high vitamin b12 level, it often presents a risk of kidney disease, liver disease, diabetes, or leukemia.

Do pregnant women need to take this test?

It has been widely observed that pregnant women tend to have lower vitamin b12 level as compared to the general population. This is because the fetus requirement of vitamin b12 increases too. Deficiency of vitamin b12 can pose a serious threat to the fetus by increasing the risk of neural tube defects in the baby by 88%. Neural tube defects are birth defects that pertain to incomplete formation of skull, brain, spine, and spinal cord. So, pregnant women must undergo this test.

Is this test prescribed for children and infants too?

Infants who are breastfed by mothers deficient in vitamin b12 will eventually develop vitamin b12 deficiency in most cases.  Also, both children and the elderly population have a lower capacity to absorb vitamin b12 from foods. So, at times infants and children might also have to go undergo a vitamin b12 test.

Are there any risks associated with vitamin b12 test?

This is a simple blood test and poses no risks or side-effects. There might be slight stinging and bruising at the site of the needle insertion. In case anything more than this is observed, you should immediately refer to a doctor.

How can I improve my vitamin b12 intake?

If you are deficient in vitamin b12, you must stick to the treatment procedure prescribed by the doctor. In addition, you can also add vitamin b12 rich foods in your diet such as dairy products (yogurt, low-fat milk, etc), hard-boiled eggs, lamb, pork, chicken, etc. If you are a vegetarian/vegan, try consuming bread, pasta, cereals, etc fortified with vitamin b12.

How common is vitamin b12 deficiency in India?

Vitamin b12 deficiency has a high prevalence in India, especially among diabetics and other endocrine disorder patients. Prevalence of vitamin B12 deficiency was 37.76% in people with pre-diabetes, 31.23% in people with endocrine problems other than diabetes and pre-diabetes and 18.25% in people with diabetes. It has been estimated that roughly 47% of the north Indian population has vitamin b12 deficiency.

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