Often referred to as “platelet concentrate”.

Recovered or apheresis

Platelets can be prepared by centrifuging a whole blood donation (often called recovered platelets) or collected by apheresis. Platelets prepared by each method have similar efficacy, but use of apheresis platelets exposes the recipient to the blood of fewer donors. The yield of platelets recovered from four to six whole blood donations should be 300x109 to 350x109 platelets in about 300 ml of plasma (the plasma is required to maintain platelet function during storage).

A single apheresis donation of platelets has comparable content of platelets and plasma. The use of a platelet additive solution allows platelets to be stored in reduced amounts of plasma. Platelet function is best maintained by storage at 22°C with agitation. As this temperature favours growth of some bacteria, some centres culture platelet concentrates prior to release from storage with the aim of reducing the risk of bacterial contamination. Platelets are generally stored for up to five days and some countries permit storage for seven days with special precautions.