EUH Morning Report: What are common abnormal red blood cell morpologies, and which diseases are they associated with?

The Bottom Line:

Certain red blood cell (RBC) morphologic findings may be related to an underlying disorder.

Abnormal Red Blood Cell Morphology

Morphologic Findings in Red Cells

Finding	Definition		Associated Conditions
Basophilic stippling	Small blue dots in red cells, due to clusters of ribosomes		Hemolytic anemias Lead poisoning Thalassemia
Pappenheimer bodies	Larger, more irregular, and grayer than basophilic stippling, due to iron-containing mitochondria		Asplenia Sideroblastic anemia
Heinz bodies Bite cells	Heinz bodies: gray–black round inclusions, seen only with supravital stains (crystal violet). Bite cells: sharp bite-like defects in red cells where a Heinz body has been removed in the spleen. Both are due to denatured hemoglobin		Oxidative injury as found in G6PD deficiency or with unstable hemoglobins
Howell–Jolly bodies Cabot rings	Howell–Jolly body: dot-like, dark purple inclusion. Cabot ring: ring-shaped dark purple inclusion. Both represent a residual nuclear fragment		Asplenia
Target cells	Red cells with a dark circle within the central area of pallor, reflecting redundant membrane		Thalassemia Hemoglobin C Liver disease
Schistocytes	Fragmented red blood cells, with forms such as helmet-shaped cells, due to mechanical red cell fragmentation		Microangiopathic hemolytic anemias (MHA): DIC, TTP, HUS, HELLP. Mechanical heart valves
Dacrocytes (teardrop cells)	Teardrop or pear-shaped erythrocytes		Can be seen in thalassemia and megaloblastic anemia Often seen in myelophthisis
Echinocytes (burr cells)	Red blood cells that have circumferential undulations or spiny projections with pointed tips		Uremia Gastric cancer Pyruvate kinase deficiency
Acanthocytes (spur cells)	Red blood cells that have circumferential blunt and spiny projections with bulbous tips		Liver disease Abetalipoproteinemia McLeod phenotype
Spherocytes	Red cells without central pallor due to decreased red cell membrane		Immune hemolytic anemia Hereditary spherocytosis
Elliptocytes	Red cells twice as long as they are wide		Iron deficiency Hereditary elliptocytosis
Stomatocytes	Red cells whose area of central pallor is elongated in a mouth-like shape		Alcohol abuse Dilantin exposure Rh null phenotype (absence of Rh antigens) Hereditary stomatocytosis

Rashidi HH and Green R. (2018) Red Blood Cell Morphology and Indices With Clinical Chemistry Interface. In Tietz Textbook of Clinical Chemistry and Molecular Diagnostics, 6e. Elsevier: Philadelphia.

Mais DD. (2019). Diseases of red blood cells. In Laposata’s Laboratory Medicine: Diagnosis of Disease in the Clinical Laboratory, 3e. McGraw Hill: New York.