Active Vitamin B12

The Active Vitamin B12 test (also known as the holo-transcobalamin or holo-TC test) determines the portion of Vitamin B12 that the body can use directly. This is the most biologically active form – it is this form that enters the cells and participates in vital processes, such as the functioning of the nervous system and blood production.

Unlike the total Vitamin B12 test, which includes the "inactive" form of this vitamin, the active B12 test helps to more accurately assess whether the body truly has enough of this important substance.

Why is this test important?

The Active B12 test is valuable because:

• It helps to detect deficiency at an early stage, even before clear symptoms or changes in the blood appear.
• It is useful when the total Vitamin B12 level appears normal, but there is still fatigue, weakness, memory disturbances, or tingling in the limbs.
• It can be especially important for people who belong to risk groups – vegetarians, vegans, older adults, pregnant women, or those with digestive disorders (e.g., low stomach acidity or intestinal diseases).
• It helps to avoid serious consequences, such as nerve damage or megaloblastic anemia, which develop with prolonged deficiency.

When is it worth taking this test?

• If you experience non-specific symptoms, but other blood tests are normal.
• If you have dietary restrictions (e.g., do not consume animal products).
• If you want to proactively check your B12 status, especially if there is a higher risk due to age or health condition.