CD41, also known as Integrin α-IIb or GPαIIb, is a protein expressed on platelets and megakaryocytes. CD41 is a component of the platelet membrane glycoprotein complex and non-covalently associates with CD61 (Integrin β-3) to form the αIIbβ3 complex, which is an essential integrin in platelets. It plays a crucial role in platelet activation and aggregation, particularly during thrombus formation and hemostasis. In clinical practice, the detection of CD41 is essential for diagnosing and studying platelet-related diseases. For instance, immunostaining for CD41 can help identify micromegakaryocytes, which might be confused with primitive megakaryocytes or lymphocytes in Wright-Giemsa staining, leading to missed diagnoses. CD41 staining can significantly improve the detection rate of micromegakaryocytes, which is crucial for the diagnosis and therapeutic monitoring of certain hematological disorders.