Lifespan of transfused platelets is
**Core Concept**
Transfused platelets have a limited lifespan due to the clearance mechanism mediated by splenic macrophages, which recognize the platelets as foreign. This process is facilitated by the presence of antigens on the platelet surface. The average lifespan of transfused platelets is around 5-7 days, which is shorter than the lifespan of autologous platelets.
**Why the Correct Answer is Right**
The correct answer is due to the splenic clearance mechanism, which involves the recognition of platelet antigens by splenic macrophages. This process is mediated by the Fcγ receptor, which binds to the Fc portion of IgG antibodies that are directed against platelet antigens. The IgG antibodies are produced in response to the transfused platelets being recognized as foreign. The splenic macrophages then phagocytose the platelets, leading to their clearance from the circulation.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as the lifespan of transfused platelets is actually shorter than that of autologous platelets.
**Option B:** This option is incorrect as the lifespan of transfused platelets is not significantly influenced by the storage conditions.
**Option C:** This option is incorrect as the lifespan of transfused platelets is not directly related to the volume of the transfusion.
**Clinical Pearl / High-Yield Fact**
To improve the lifespan of transfused platelets, it is essential to minimize the volume of the transfusion and to use platelets that have been stored under optimal conditions. Additionally, the use of platelet antibodies can be a useful strategy to enhance the survival of transfused platelets.
**Correct Answer: C. 7 days**