Many cells in our body need vitamin B12, including nerve cells and blood cells. Inadequate vitamin B12 gradually affects sensory and motor nerves, causing neurological problems to develop over time. It is important to know that the neurological effects of vitamin B12 deficiency may be seen before anemia is diagnosed.

The anemia also affects the gastrointestinal system and the cardiovascular system. The following symptoms may indicate pernicious anemia:

• shortness of breath
• fatigue
• pallor
• rapid heart rate
• loss of appetite
• diarrhea
• tingling and numbness of hands and feet
• sore mouth
• unsteady gait, especially in the dark
• tongue problems
• smell, impaired
• gums, bleeding
• positive Babinski's reflex
• loss of deep tendon reflexes
• personality changes, "megaloblastic madness"

Tests that may indicate pernicious anemia include:

• CBC results that show low hematocrit and hemoglobin with elevated MCV (low red blood cell count with large-sized red blood cells)
• CBC showing low white blood count and low platelets
• low reticulocyte count
• bone marrow examination (only needed if diagnosis is unclear)
• serum LDH
• below normal serum vitamin B-12 level
• Schilling test
• measurement of serum holotranscobalamin II
• measurment of methylmalonic acid (MMA)

This disease may also alter the results of the following tests:

• TIBC
• peripheral smear
• leukocyte alkaline phosphatase
• gastrin
• cholesterol test
• bilirubin