Target cells on a blood smear are indicative of which condition?

Target cells, also known as Codocytes, are red blood cells that have an abnormal morphology presenting with a central area of pigmentation surrounded by a thin ring of cytoplasm and an outer ring of pallor. The presence of target cells is primarily associated with several conditions, but their most characteristic association is with liver disease.

In liver disease, particularly conditions leading to cholestasis or hepatic dysfunction, lipid metabolism is altered, resulting in the incorporation of excess cholesterol into the erythrocyte membrane. This alteration in membrane composition can lead to the formation of target cells as they lose normal biconcave shape and adopt this characteristic target-like appearance. Additionally, in conditions such as hemoglobinopathies (like sickle cell disease) and thalassemias, the increased production of target cells can also be observed, but these are not as directly associated with liver dysfunction as a primary indication.

While certain other conditions listed may appear in different contexts of hematological studies, the direct link of target cells to liver disease is well-established. Therefore, recognizing the associated morphology on a blood smear serves as an important diagnostic clue, highlighting the underlying pathology of liver-related issues.