Recognizing the significance of poikilocytes

Learn about the clinical relevance of poikilocytes and how they can affect lab results.

Amer Wahed, MD FRCPath
Amer Wahed, MD FRCPath
5th May 2018 • 3m read

Pathologists frequently mention various poikilocytes when reporting on peripheral blood smears. After watching this video from our Hematology and Coagulation Essentials course, you'll understand the clinical relevance of poikilocytes and be able to determine which additional tests to order and when.

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Video Transcript

[00:00:00] From time to time, various poikilocytes are mentioned in a pathology report. Poikilocytes are abnormally shaped red cells. One of the most common types of poikilocytes are sickle cells. The significance of this cell type is easy to understand. Presence of sickle cells mean that the patient most likely has sickle cell disease. If there is no previous diagnosis, the next step is to order hemoglobin electrophoresis.

[00:00:30] Spherocytes are red cells with no central pallor. Spherocytes are commonly present in patients with hereditary spherocytosis and autoimmune hemolytic anemia. If spherocytes are identified in a peripheral blood smear, additional testing for hemolytic anemia is indicated. This is done by a DAT. A positive DAT means that there are antibodies or compliment on red cell surface. If hereditary spherocytosis is suspected,

[00:01:00] osmotic fragility test may be ordered. Elliptocytes and stomatocytes—individuals with increased elliptocytes in their peripheral smear may have hereditary elliptocytosis, and individuals with increased stomatocytes in their peripheral blood may have hereditary stomatocytosis. Other than hereditary elliptocytosis, elliptocytes may also be seen in iron deficiency anemia. Other than hereditary stomatocytosis,

[00:01:30] stomatocytes may also be seen in individuals who do not possess the Rh antigen on their red cell surface, called Rh null disease. The presence of teardrop red cells may imply bone marrow infiltration, for example, due to bone marrow fibrosis, called myelofibrosis. In such cases, there may also be immature red cells and white cells in the circulation. This condition is called leukoerythroblastic blood picture. Let us now move on to spiculated

[00:02:00] red cells. Spiculated cells describe a variety of cells all with spicules. Echinocytes possess 10 to 30 short blunt spicules. They may be seen with storage artifact, liver and kidney diseases, and pyruvate kinase deficiency. Acanthocytes, also another example of spiculated cells have 2 to 20 unequal, irregular spicules. If we see few acanthocytes, we may think of

[00:02:30] hemolytic anemia, renal disease or post splenectomy states. If the number of acanthocytes are numerous, we should think of abetalipoproteinemia. Keratocytes usually have a pair of spicules and they are mainly seen in microangiopathic hemolytic anemia and renal disease. Schistocytes, which represent fragmented red cells are seen in microangiopathic hemolytic anemia. Examples of microangiopathic hemolytic

[00:03:00] anemia include disseminated intravascular coagulation or DIC, thrombotic thrombocytopenic purpura or TTP, and hemolytic uremic syndrome, HUS. Target cells may sometimes be seen in the peripheral smear and these are formed as a consequence of the presence of excess membrane in relation to the volume of cytoplasm. They may be seen in hemoglobinopathies or thalassemias. Target cells may also be seen in liver disease,

[00:03:30] especially obstructive liver disease, post-splenectomy states, and in patients with iron deficiency. All of these different red cell shapes have unique differential diagnosis and appropriate testing may be ordered to find out the final underlying cause.