How long can blood be stored with CPD-A ?
**Core Concept**
The storage of blood with CPD-A (Citrate-Phosphate-Dextrose-Adenine) is a method to preserve red blood cells for transfusion. CPD-A is a type of anticoagulant-preservative solution that maintains the viability of red blood cells by providing energy sources and preventing clotting.
**Why the Correct Answer is Right**
Blood stored with CPD-A can be safely transfused for up to 35 days. This is because CPD-A contains adenine, which is a precursor to ATP, and glucose, which provides energy for red blood cells. Additionally, citrate and phosphate help to prevent clotting and maintain the pH balance. The combination of these components allows for the storage of blood for an extended period without significant loss of viability.
**Why Each Wrong Option is Incorrect**
**Option A:** 21 days. This is incorrect because CPD-A allows for longer storage, up to 35 days.
**Option B:** 42 days. This is incorrect because there is no established safe storage time for blood beyond 35 days.
**Option C:** 49 days. This is incorrect for the same reason as Option B.
**Clinical Pearl / High-Yield Fact**
It's essential to note that blood storage times may vary depending on the storage conditions, such as temperature and agitation. Always verify the storage duration and conditions before transfusing stored blood.
**Correct Answer:** C. 35 days.