Vitamin B12 and Folate

Other names: Folic Acid; Vitamin B12 or Cobalamin; RBC Folate

Vitamin B12 and folate are part of the B complex of vitamins; these vitamins are needed for the formation of red blood cells, DNA synthesis and tissue repair. Good sources of folate include leafy green vegetables, citrus fruits and liver and good sources of vitamin B12 include red meat, milk, eggs and fish.

Why is the test used?

The test is usually used to identify the root of anaemia or damage to the nerves (also known as neuropathy). The test is usually carried out after a full blood count; if the test reveals that the individual has large red blood cells, the B12 and folate test may be recommended.

The test is also used to monitor the progress of treatment in patients that have been diagnosed with a vitamin B12 or folate insufficiency.

Doctors usually order the test if a patient has symptoms of nerve damage (including tingling, numbness and burning sensations) or changes in their mental state (this is more prevalent in older people). The test can also be recommended when a patient has symptoms of B12 and folate deficiency, which includes:

  • Weakness
  • Fatigue
  • Dizziness
  • A painful mouth (or tongue)

How is the test done?

The test is done by taking a sample of blood from a vein in the arm. A needle will be inserted into the vein and blood will be collected in a syringe, which is attached to the needle. Once the doctor has a sufficient sample, they will bottle the sample and label it with the patient’s name; the sample will then be sent away to the laboratory for analysis.

What do the test results mean?

If a person has low levels of vitamin B12 or folate, this will usually indicate that they have a deficiency; further tests will usually be carried out to investigate the harshness of the condition.

If an individual is taking supplements to boost their levels and the test shows that levels have increased, this will indicate that the treatment has been successful.

In some cases, high levels of vitamin B12 may be caused by leukaemia or liver conditions, while high levels of folate may be caused by pernicious anaemia (this occurs when the body does not make sufficient supplies of a protein known as intrinsic factor).

Specific Blood Tests



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