A healthy diet must include Vitamin B12. For our body to produce enough red blood cells and maintain a healthy neural system, this vitamin must be present in constant amounts. Low levels of B12 are not common in the majority of individuals who adhere to a nutritious diet. They might, however, fall below average for a variety of causes. Pernicious anaemia, sometimes referred to as megaloblastic anaemia, is caused due to a Vitamin B12 deficiency and causes a decline in red blood cells. Whether the levels are normal, low, or in between can be determined by a quick blood test.

What is a Vitamin B12 Test?

Vitamin B12 level testing measures the amount of Vitamin B12 present in a person's blood or urine to assess the body's total vitamin B12 reserves. Generally, vitamin B12 concentrations range from 190-950 picograms per ml; however, the measurement method used will vary from laboratory to laboratory. A folic acid test is usually done in conjunction with a Vitamin B12 blood test because a deficiency of either Vitamin B12 or both can cause anaemia. A doctor can identify any deficiencies and suggest the best course of therapy with the use of Vitamin B12 level testing.

Purpose of Vitamin B12 Test

Vitamin B12 testing is conducted to identify whether an individual has a Vitamin B12 deficiency or an abnormally low B12 level in their body. In some cases, the Vitamin B12 level may be tested independently, while in other cases, it may be measured in conjunction with other tests to identify or monitor certain health conditions. Vitamin B12 deficiency test may be prescribed by a physician if an individual exhibits anaemia or neurological symptoms such as mental alteration, lack of balance or immobility, pain, or numbness in the hands and feet. Additionally, a Vitamin B12 test may be prescribed as a follow-up if an individual has had a blood test that indicates the presence of abnormally large red blood cells, which are associated with the development and regulation of anaemia.

What happens during the Vitamin B12 test?

To check a patient's vitamin B12 level, doctors often draw blood, although there are also at-home urine tests available. A standard type of blood test can be used to determine whether vitamin B12 levels are normal. It is important to inform the doctor of any medications or supplements taken by the patient, as some of these substances may influence the results of the Vit B 12 test. For around six to eight hours before the test, the healthcare expert will advise not eating or drinking anything other than water. 

Procedure for Vitamin B12 Test

A blood sample is required for Vitamin B12 testing. This sample is typically taken from the patient’s arm. If the patient opts for an at-home Vitamin B12 testing kit, they will be provided with the necessary supplies to collect the blood sample. Certain micronutrient testing at-home kits may screen for Vitamin B12 and other micronutrients through a urine sample or hair sample.

• It is recommended that individuals complete a six to eight-hour fasting period prior to undergoing a Vitamin B12 blood test.
• A band may be wrapped around the upper arm by the medical professional taking the blood sample to make it simpler to locate the veins. 
• A sample tube is attached to the vein, and a needle is used to draw a small amount of blood into the tube, which may cause a slight sting. The entire process typically takes less than one minute.
• The patient may be advised to apply mild pressure to the area where the blood has been extracted with a cotton swab, gauze or bandage, followed by the application of a bandage to the area where the blood has been extracted.

Uses of Vitamin B12 Test

If a person exhibits symptoms that point to a potential deficiency in one or more B vitamins, a Vitamin B12 deficiency blood test is utilised. For instance, a Vitamin B12 and folate test is frequently used for signs of particular forms of anaemia. Even if there are no symptoms, the doctor may still examine the vitamin B levels if the patient has a disease that raises their risk for a vitamin B deficiency. This vitamin B12 test is also used in the event of nervous system-related symptoms. Below are some other reasons of Vitamin B12 test uses:

• To track nerve anomalies like peripheral neuropathy.
• When there is a balance problem
• If one experiences symptoms such as weakness and decreased appetite.
• To know what causes a mouth ulcer.

Vitamin B12 testing can be done on its own or in conjunction with other blood tests.

When to take the Vitamin B12 Test

A Vitamin B12 test is typically recommended in the following situations:

• Symptoms of Deficiency: If you are experiencing symptoms of Vitamin B12 deficiency, such as fatigue, weakness, pale or jaundiced skin, shortness of breath, dizziness, numbness or tingling in the hands and feet, difficulty walking, or cognitive issues, a B12 test may be advised.
• Vegetarian or Vegan Diet: Individuals following a strict vegetarian or vegan diet are at a higher risk of B12 deficiency, as this vitamin is primarily found in animal products. Regular testing may be recommended for those with limited B12 intake from their diet.
• Digestive Disorders: Conditions that affect the absorption of nutrients in the digestive system, such as pernicious anemia, celiac disease, Crohn's disease, and atrophic gastritis, can lead to B12 deficiency. Testing may be necessary for individuals with these conditions.
• Age and Medical History: Older adults are more prone to B12 deficiency, and routine testing may be suggested, especially for those over 50. Individuals with a history of gastric bypass surgery may also need regular B12 monitoring.
• Certain Medications: Long-term use of medications that reduce stomach acid, like proton pump inhibitors or certain antacids, can impact B12 absorption. Those on such medications may require periodic B12 testing.
• Pregnancy: Pregnant women may be advised to have their B12 levels checked, as deficiency can affect both the mother and the developing baby.

How to Prepare For the Vitamin B12 Test?

It is usually advised that individuals abstain from consuming food or beverages for approximately 6 to 8 hours prior to the test. But, it is essential to maintain adequate hydration levels, so drinking water is allowed. Certain types of medications might affect the results of the test. The healthcare provider will advise if any medications need to be discontinued. It is not recommended to discontinue any medications prior to consultation with the healthcare provider. It is imperative to adhere to the instructions of the concerned healthcare professional to ensure that the test results are accurate and avoid any discrepancies.

Risks of Vitamin B12 Test

While Vitamin B12 tests are generally considered safe and are routinely conducted, there are minimal risks associated with the procedure. Here are some potential considerations:

• Discomfort or Pain: The test involves drawing blood, which may cause slight discomfort or pain at the site of the needle insertion. However, this is typically brief.
• Bruising or Bleeding: After the blood is drawn, there may be a small risk of bruising or bleeding at the puncture site. Applying pressure to the area can help minimize this risk.
• Fainting or Dizziness: Some individuals may feel faint or dizzy during or after the blood draw. It's advisable to inform the healthcare professional if you have a history of fainting or if you feel lightheaded.
• Infection: There is a very low risk of infection at the site where the needle is inserted. Healthcare professionals use sterile techniques to minimize this risk.
• Hematoma Formation: In rare cases, a hematoma (a collection of blood outside blood vessels) may form at the puncture site. Applying proper pressure and following post-draw care instructions can help prevent this.

Values of Vitamin B12 Test Results

Depending on the results of laboratory tests, the typical range of Vitamin B12 levels in a person's blood circulation may differ somewhat. Generally, a normal level of Vitamin B12 is between 200 and 800 pg/mL. A borderline level of 150 to 300 pg/mL is considered to be low, and further testing may be required. Below 150 pg/mL, further testing is necessary. In some cases, a doctor may additionally check the blood folate level of a patient since low folate levels can cause symptoms similar to those of low B12.

Conclusion

Vitamin B12 level tests are prescribed as part of routine medical check-ups, as part of pre-pregnancy screening, or to provide definitive proof of an underlying condition. At CARE Hospitals, the Vitamin B12 blood test cost is relatively low and is performed at both in-patient hospitals and diagnostic centres.

FAQs

1. What happens when your Vitamin B12 is low?

Ans. A deficiency of Vit B12 can lead to a range of neurological and cognitive symptoms, including numbness, muscle weakness, and mental health issues, such as mild depression and anxiety, as well as confusion and dementia.

2. What happens when your B12 levels are too high?

Ans. Excessive levels of Vitamin B12 may result in frequent headaches. It can also cause gastrointestinal issues such as diarrhoea, nausea and vomiting. Additionally, elevated Vitamin B12 levels may result in fatigue and weakness. High levels of Vitamin B12 may cause tingling in the hands and feet.

3. What are the first signs of B12 deficiency?

Ans. Signs & symptoms of Vitamin B12 deficiency may include numbness, muscle weakness, difficulty walking, loss of appetite, nausea, tiredness, and elevated heart rate.

4. How long does it take for B12 supplements to work?

Ans. It may take a period of several weeks for Vitamin B12 levels to return to normal and for symptoms (e.g., extreme fatigue or lethargy) to subside after taking supplements.

Reference:
https://www.webmd.com/a-to-z-guides/vitamin-b12-test

https://www.medicalnewstoday.com/articles/322286#:~:text=A%20vitamin%20B%2D12%20level%20test%20checks%20the%20amount%20of,will%20depend%20on%20the%20laboratory.

https://medlineplus.gov/lab-tests/vitamin-b-test/#:~:text=What%20is%20it%20used%20for,of%20certain%20types%20of%20anemia.

https://www.ucsfhealth.org/medical-tests/vitamin-b12-level#:~:text=You%20should%20not%20eat%20or,before%20talking%20to%20your%20provider