A system for obtaining plasma enriched in platelets is disclosed which is closed to the atmosphere. The system includes: a collection tube containing an anticoagulant portion and a separation gel； a first collection syringe adapted to collect a portion of fluid relatively depleted in platelets from said collection tube after centrifugation； and a second collection syringe adapted to collect plasma enriched in platelets from said collection tube after centrifugation, said second collection syringe further comprising a filter unit adapted to filter cells included in said plasma enriched in platelets.
