Platelet storage

Storage condition

• Temperature: 20-24C
• Continuous platform agitator
• pH balance: Need to be 6.2-7.8
• Stored in bags that allow gas exchange
  * Polyolefin plastic [PK1:p254]

Temperature of storage

Platelets in stored bloods are stored at 4C
--> Irreversible disc-to-sphere transformation due to microtubule disassembly
--> Non-functional

Thus in stored blood, platelet function is poor or absent

Gas exchange during storage

Production of lactic acid and carbon dioxides lowers the pH

Thus, gas exchange (via special bag and constant mild agitation)
--> Promote aerobic metabolism
--> Minimise lactic acid production and promote loss of CO2

Risk of infection

• Due to storage at room temperature
  --> Main clinical risk = sepsis
• Storage time is limited to 5 days to minimise risk of sepsis

Other notes

• A unit of platelet increases platelet count by 5,000 to 10,000 per microliter (or mm³)
• A unit of platelet contains about 6 x 10^10 platelets
• A unit of platelet is obtained from 4-6 units of blood
• Nearly 1/3 of transfused platelets are sequestered in the normal spleen