Vitamin deficiencies, macrocytic anemia, or pernicious anemia is a decrease in red blood cells, that occurs when the body cannot properly absorb vitamin B12 from the digestive tract. Our doctors diagnose vitamin deficiency through blood tests that check the following:
The amount and appearance of red blood cells. In vitamin deficiency related to lack of vitamin B12 and folate, red blood cells are large and underdeveloped. In advanced deficiencies, a number of white blood cells and platelets could also decrease and have an abnormal appearance under the microscope.