Vitamin B12 (Active and Total) Blood Test

About the Vitamin B12 Blood Test

Check and manage the level of vitamin B12, both active and total, in your body with this test. Vitamin B12 is essential for most body systems, particularly in haematology with the manufacture of blood cells and hence healthy function of the organism as a whole, including the nervous system. Symptoms of low vitamin B12 are abundant, including tiredness, lack of energy, headaches and many others.

This test measures both active and total levels of Vitamin B12

Total B12 refers to the measurement of all forms of vitamin B12 present in the blood. This includes both active B12 (methylcobalamin and adenosylcobalamin) and inactive B12 forms (such as cyanocobalamin). The measurement of total B12 provides an overall picture of the total B12 content in the bloodstream, regardless of whether the B12 forms are actively available for body use.

Active B12, also known as cobalamin, refers to the biologically active forms of vitamin B12 that are immediately available for the body to use. The two primary active forms are methylcobalamin and adenosylcobalamin. These active forms play essential roles in various physiological processes, particularly in energy metabolism and nerve function.

Why it's important to measure both.

The distinction between total B12 and active B12 is crucial because not all forms of B12 are biologically active or readily usable by the body. Cyanocobalamin, for example, is an inactive form of B12 that requires conversion into active forms before the body can utilise it. Methylcobalamin and adenosylcobalamin are already in their active forms and can be directly utilized by cells.

In some cases, only total B12 levels are measured, which may not give a complete assessment of B12 status. It is often beneficial to measure active B12 levels (or other markers like free B12/holotranscobalamin) to better understand the body's immediate access to functional B12.

This test measures both forms.

2 Biomarkers