Macrocytic anemia is a type of anemia that causes unusually large red blood cells. Like other types of anemia, macrocytic anemia means that the red blood cells also have low hemoglobin.
Hemoglobin is an iron-containing protein that transports oxygen around the body. Deficiencies in vitamin B-12 or folate often cause macrocytic anemia, so it is sometimes called vitamin deficiency anemia.
Macrocytic anemia occurs if the red blood cells are unusually large. A unit called femtoliters (fL) is used to measure the size of blood cells. Usually, red blood cells are between 80?100 fL.
Red blood cells larger than 100 fL are considered macrocytic. When the cells grow too large, there are fewer of them than there needs to be and they carry less hemoglobin. This means the blood is not as oxygen-rich as it should be. Low blood oxygen can cause a range of symptoms and health problems.
Macrocytic anemia is not a single disease, but a symptom of several medical conditions and nutritional problems.
One of the most common types of macrocytic anemia is megaloblastic macrocytic anemia. This happens when red blood cells produce DNA too slowly to divide.
Macrocytic anemia can be broken into two main types: megaloblastic and nonmegaloblastic macrocytic anemias.
Most macrocytic anemias are also megaloblastic. Megaloblastic anemia is a result of errors in your red blood cell DNA production. This causes your body to make red blood cells incorrectly.
Possible causes include:
Nonmegaloblastic forms of macrocytic anemia may be caused by a variety of factors. These can include:
