target cells
Red blood cells with a characteristic bull's-eye appearance on blood smear, commonly seen in hemoglobinopathies and liver disease.
Full Definition
Target cells, also called codocytes, are red blood cells that appear to have a dark center surrounded by a clear ring and dark outer rim, resembling a target or bull's-eye. They form when there is an increased surface area-to-volume ratio, often due to excess membrane or decreased hemoglobin content. In pediatric hematology, target cells are characteristic findings in hemoglobin C disease, thalassemia syndromes, sickle cell disease (particularly HbSC), and liver disease. They can also be seen in iron deficiency anemia and after splenectomy. The percentage of target cells can help differentiate between various hemoglobinopathies.
Usage
Usage note: Also called codocytes; percentage can help distinguish between different hemoglobinopathies.
In Context
- "The blood smear revealed numerous target cells, suggesting a hemoglobinopathy." — pathology report
- "Target cells comprised 30% of red blood cells, consistent with hemoglobin C trait." — laboratory report