The Vitamin B12 test measures the level of vitamin B12 (cobalamin) in the blood. Vitamin B12 is an essential water-soluble vitamin that plays a crucial role in the production of red blood cells, DNA synthesis, neurological function, and the metabolism of fatty acids and amino acids. It is found naturally in animal products such as meat, fish, eggs, and dairy, and is absorbed in the small intestine with the help of a protein called intrinsic factor.
This test is used to diagnose vitamin B12 deficiency, which can cause megaloblastic anemia (enlarged, abnormal red blood cells), peripheral neuropathy, cognitive decline, fatigue, and neurological symptoms such as numbness or tingling in the hands and feet. It is commonly ordered for individuals following a vegan or vegetarian diet, older adults, patients with gastrointestinal disorders (such as Crohn’s disease or celiac disease), and those taking medications such as metformin or proton pump inhibitors that can interfere with B12 absorption.
