Your doctor might recommend a B-12 test if you have:
- tingling in the hands and feet
- problems with balance
- a racing heart
- loss of appetite
You may also take this test if your doctor suspects you might have pernicious anemia. Pernicious anemia is a reduction in red blood cells. It occurs when your intestines can’t absorb vitamin B-12, which is necessary for red blood cell production. Symptoms are not often seen in people younger than 30 years old. The average age of diagnosis is 60.