[Concentration of platelets from apheresis: methods of preparation]

Apheresis platelet concentrates are platelet suspension obtained by apheresis from a blood cell separator. These techniques are now 20 years old. They are best way to collect great quantities of platelets from only one donor. These blood cell separators (discontinuous or continuous flow), realise extracorporeal circuit in which the blood in mixed with an anticoagulant (mainly citrate). All the procedures used are automatic and adapted with the donor parameters. The platelet donor is between 18 and 60 years old and can give 5 times per year. The platelet concentration in the product is divided into 3 classes (1 = 2 - 4 x 10(11) - 2 = 4 - 6 x 10(11) - 3 > 6 x 10(11)). Each category has a special price. Actually, we can store these platelets only 5 days. In the future, we need new studies and new directions (additive solution, new plastic) to propose a better viability and a longer storage.