Definition: A component obtained by removing the majority of leucocytes from a red cell preparation.

Properties: The leucocyte count must be less than 1x106 per unit. Mean count as low as 0.05 x 106 are achievable. Each unit must have a maximum haemoglobin content of 40grms.

Methods of preparation: Various techniques are used to produce this preparation including buffy-coat depletion and filtration. The best results are currently achieved using a combination of both these methods.

Storage: After collection blood should be kept under controlled temperature between 2 degrees celcius and 6 degrees celcius. Temperature should not exceed 10 degress celcius. Expiry date under these condition depends on the anticoagulant used. Example: using CPDA-1 the storage time is 35 days.

Alternatively, whole blood can be kept up to 24hrs in controlled temperature of between 20 degrees celcius and 24 degrees celcius, if platelets are to be prepared from the particular whole blood.