Macroovalocytes are enlarged, oval-shaped

erythrocytes Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...

(red blood cells). They are not seen in healthy blood, and are most commonly seen in

megaloblastic anemia Megaloblastic anemia is a type of macrocytic anemia. An anemia is a red blood cell defect that can lead to an undersupply of oxygen. Megaloblastic anemia results from inhibition of DNA synthesis during red blood cell production. When DNA synthe ...

. In most instances, the macroovalocyte morphology is due to megaloblastic erythropoiesis (

Vitamin B-12 Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. It is one of eight B vitamins. It is required by animals, which use it as a cofactor in DNA synthesis, in both fatty acid and amino acid metabolism. I ...

folate Folate, also known as vitamin B9 and folacin, is one of the B vitamins. Manufactured folic acid, which is converted into folate by the body, is used as a dietary supplement and in food fortification as it is more stable during processing and ...

deficiency) but may be seen with

dyserythropoiesis Dyserythropoiesis refers to the defective development of red blood cells, also called erythrocytes. This problem can be congenital, acquired, or inherited. Some red blood cells may be destroyed within the bone marrow during the maturation process, ...

. Although macroovalocytes are characteristic in these deficiency states, they are not pathognomonic.

Poikilocytosis Poikilocytosis is variation in the shapes of red blood cells. Poikilocytes may be oval, teardrop-shaped, sickle-shaped or irregularly contracted. Normal red blood cells are round, flattened disks that are thinner in the middle than at the edges. ...

is often present, particularly in more advanced cases. If associated with hypersegmented granulocytes in the absence of other causes (e.g. drugs), the findings are essentially diagnostic of Vitamin B-12 or folate deficiency.

References

{{Reflist Blood cells