Blood when stored at 4degC can be kept for
**Core Concept**
Blood can be stored at refrigerated temperatures, but its shelf life is limited by the risk of bacterial contamination and coagulation disorders. The storage conditions for blood are crucial to maintain its viability and safety for transfusion.
**Why the Correct Answer is Right**
When stored at 4°C, blood can be kept for up to 35 days. This is because the cold temperature slows down the metabolic processes of the blood cells, reducing the risk of bacterial growth and coagulation. The storage conditions also help to maintain the integrity of the red blood cells and prevent hemolysis. The American Association of Blood Banks (AABB) and other regulatory bodies have established guidelines for the storage of blood, which include a maximum storage period of 35 days at 4°C.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because blood cannot be stored for an indefinite period at room temperature (20-25°C). At higher temperatures, bacterial growth and coagulation disorders are more likely to occur, making the blood unsafe for transfusion.
**Option B:** This option is incorrect because blood cannot be stored for a prolonged period at body temperature (37°C). At this temperature, the metabolic processes of the blood cells are accelerated, leading to bacterial growth and coagulation disorders.
**Option C:** This option is incorrect because blood cannot be stored for an extended period at -20°C. While freezing can preserve blood for an extended period, it is not a common practice due to the risk of hemolysis and the need for specialized equipment.
**Clinical Pearl / High-Yield Fact**
When storing blood, it is essential to maintain a temperature of 2-6°C and monitor its viability and safety through regular testing. Blood that has been stored for an extended period should be thoroughly evaluated before transfusion to ensure its safety and efficacy.
**Correct Answer: D. 35 days**