What it means
The serum vitamin B12 is checked when a client has large red blood cells (macrocytic anemia), numbness or tingling in the hands and feet, memory changes, or risk factors for low B12: older age, pernicious anemia, stomach or bowel surgery, a vegan diet, and long-term metformin or acid-reducing drugs. Borderline results are often followed by other tests.
At a glance
| Normal range | About 200–900 pg/mL [148–664 pmol/L]; below 200 pg/mL is deficient and 200–300 pg/mL borderline. |
|---|---|
| Also written | serum B12, B12 level, cobalamin level |
Related terms
anemia
A lower than normal number of red blood cells or amount of hemoglobin in the blood.
vitamin B12
A vitamin from animal foods that the body needs to make red blood cells and keep nerves healthy; also called cobalamin.
pernicious anemia
An anemia from a lack of vitamin B12 because the stomach does not make intrinsic factor, a protein needed to absorb it.
folate level
A blood test that measures folate (folic acid), a B vitamin needed to make red blood cells and DNA.