Red Blood Cell Morphology

2021-02-24 12:00 AM

Abnormal size is called anisocytosis (aniso means unequal). An abnormal shape is called poikilocytosis (poikilo means various).

Red Cell Shapes

Abnormal size is called anisocytosis (aniso means unequal). An abnormal shape is called poikilocytosis (poikilo means various). Elliptocytes may be seen in hereditary elliptocytosis. Spherocytes result from decreased erythrocyte membrane and they may be seen in hereditary spherocytosis and in autoimmune hemolytic anemia. Target cells result from increased erythrocyte membrane, and they may be seen in hemoglobinopathies, thalassemia, and liver disease. Acanthocytes have irregular spicules on their surfaces; numerous acanthocytes can be seen in abetalipoproteinemia. Echinocytes (burr cells) have smooth undulations on their surface; they may be seen in uremia or more commonly as an artifact.

Schistocytes are erythrocyte fragments (helmet cells are a type of schistocyte); they can be seen in microangiopathic hemolytic anemias or traumatic hemolysis. Bitecells are erythrocytes with “bites” of cytoplasm being removed by splenic macrophages; they may be seen in G6PD deficiency. Teardrop cells (dacrocytes) may be seen in thalassemia and myelofibrosis. Sickle cells (drepanocytes) are seen in sickle cell anemia. Rouleaux (“stack of coins”) refers to erythrocytes lining up in a row. Rouleaux are characteristic of multiple myeloma.

Red Cell Inclusions

Basophilic stippling results from cytoplasmic remnants of RNA; it may indicate reticulocytosis or lead poisoning. Howell-Jolly bodies are remnants of nuclear chromatin that may occur in severe anaemias or patients without spleens. Pappenheimerbodies are composed of iron, and they may be found in the peripheral blood following splenectomy. Ring sideroblasts have iron trapped abnormally in mitochondria, forming a ring around the nucleus; they can be seen in sideroblastic anemia. Heinz bodies result from denatured hemoglobin; they can be seen with glucose-6-phosphate dehydrogenase deficiency.