Vitamin B12 (Cobalamin) Mass Concentration in Blood

Why This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms like fatigue, numbness, weakness, or unexplained anemia. It’s also used to screen for conditions like pernicious anemia, vitamin B12 deficiency, or malabsorption disorders (e.g., celiac disease). Some people with certain genetic conditions or those on long-term medications (like proton pump inhibitors) are at higher risk.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the draw if your blood is collected early in the morning. Bring your medical records or a list of current medications to your appointment.

How the Test Works

A small amount of blood is drawn from a vein in your arm. The test measures the vitamin B12 concentration in your blood using a specialized laboratory method to detect its presence.

What the Results Mean

Results are compared to standard reference ranges for healthy individuals. Low levels may indicate deficiency, while high levels could suggest conditions like kidney disease or certain cancers. Your doctor will interpret results in the context of your symptoms and medical history.