This test is used to measure the levels of active vitamin B12 (hydroxycobalamin), essential for healthy nerves, blood cells and DNA. This test is essential for people who do not get any vitamin B12 in their diets e.g. Vegans. Elderly people are also at greater risk of deficiency.
This test includes (expand individual tests for details):
Vitamin B12 is essential for the production of red blood cells which carry oxygen around the body. Prolonged deficiency of vitamin B12 can also cause nerve damage. It is almost only found in meat and animal food products. This test measures the level of unbound or active B12 which is available for your cells. Low levels cause fatigue and low energy levels. Raised levels can be due to a blood or liver disorder.