The test is usually ordered if a blood count test shows a higher concentration of red blood cells and a decrease in hemoglobin level. The test can be used to diagnose macrocytic anemia.
It can help to find the cause of neuropathies (limb numbness, burning, tingling sensation).
For elder people, in the case of changes in the state of mind and behavior (depression, confusion), a test is requested to determine vitamin B12 levels.
The test is also recommended in case of indigestion or malabsorption (eg gluten sensitivity, Crohn’s disease, colitis).
A blood sample, taken from a vein, is needed for the test.