Vitamin B12

Function

Vitamin B12, also known as cobalamin, is a water-soluble vitamin that plays a critical role in the formation of red blood cells, cell metabolism, nerve function, and the production of DNA. It is unique among vitamins because it contains a metal ion (cobalt) and requires a specific protein called intrinsic factor, produced in the stomach, for absorption in the small intestine.

Why it is Ordered

This test is primarily ordered to diagnose the cause of anemia or neuropathy. It is also used to evaluate nutritional status in individuals with restrictive diets (like vegans), malabsorption syndromes, or those showing cognitive changes. Physicians often order it alongside a Folate test because the two vitamins work closely together.

Associated Conditions

• Pernicious Anemia: An autoimmune condition where the body cannot produce intrinsic factor.
• Megaloblastic Anemia: A condition where red blood cells are larger than normal and fewer in number.
• Peripheral Neuropathy: Nerve damage often resulting in numbness or tingling in hands and feet.
• Atrophic Gastritis: Thinning of the stomach lining which reduces acid and intrinsic factor production.
• Crohn's Disease: An inflammatory bowel disease that can impair absorption in the terminal ileum.