8 Echinocytes (Burr Cells)
Michelle To and Valentin Villatoro
The red blood cell has multiple evenly distributed projections that are of equal length that cover the entire surface of the cell.1 Cells usually have an area of central pallor.2
Commonly form due to a “glass effect” during peripheral blood smear preparation with glass slides. Glass slides can release basic substances that can induce echinocyte formation.3
Another cause of echinocyte formation is due to storage conditions. Echinocytes can naturally form in whole blood that has been stored at 4℃ after a few days (i.e. Blood to be transfused).3
The formation of echinocytes is a reversible process and can reform a natural discoid shape.3
Echinocytes are often considered artifact from the smear making process (drying or staining) and may not be reported, depending on individual laboratory protocol.
Associated Disease/Clinical States:1-3
Pyruvate Kinase (PK) Deficiency
Microangiopathic Hemolytic Anemias (MAHAs)
1. Ford J. Red blood cell morphology. Int J Lab Hematol [Internet]. 2013 Mar 9 [cited 2018 Jul 12];35(3):351–7. Available from: https://doi.org/10.1111/ijlh.12082
2. Rodak BF, Carr JH. Variations in shape and distribution of erythrocytes. In: Clinical hematology atlas. 5th ed. St. Louis, Missouri: Elsevier Inc.; 2017. p. 93-106.
3. Landis-Piwowar K, Landis J, Keila P. The complete blood count and peripheral blood smear evaluation. In: Clinical laboratory hematology. 3rd ed. New Jersey: Pearson; 2015. p. 154-77.